Threema started life as an abbreviation: “EEEMA”, for “End-to-End Encrypted Messaging Application”. The three “E”s were a bit unwieldy, so it became “Threema”.
Threema is the world’s favorite secure messenger. It sets itself apart from others in the following respects:
- Guaranteed privacy: Threema is designed to generate as little data on servers as technically possible.
- Full anonymity: You are not forced to provide any personal information (such as your phone number or email address) in order to use Threema.
- Comprehensive encryption: With Threema, all your communications are end-to-end encrypted – not only text messages but also group chats, media files, and even status messages.
- Comprehensive functionality: Threema is versatile and feature-rich.
- Open standards: Threema uses a cryptographic library which is open source.
Threema sets itself apart from other encrypted messengers in many respects, not only in terms of functionality or the encryption quality but also in regard to privacy protection. Learn more.
In contrast to other messengers, your identity in Threema does not depend on a phone number. Each Threema user gets a randomly generated, 8 digit Threema ID when starting the app for the first time. This ID is your unique address in Threema and makes it possible to use Threema completely anonymously, without disclosing any personal information.
Your Threema ID is just one of two components that make up your identity in Threema. The other one is the so called key pair (consisting of a public key and a private key) which is essential for the encryption. Your Threema ID is permanently tied to your public key. While the public key is sent to Threema's servers to be distributed to your chat partners, the private key remains on your device where it is securely stored. All messages directed to you will be individually encrypted with your public key on the sender's device. They can only be decrypted with your personal private key.
|Android||iOS||Windows Phone||Blackberry||Amazon Fire OS|
|Wearables* (e.g. Smartwatch)||Apple Watch|
|Android Auto||Apple CarPlay|
Threema is fully supported.
You can use Threema with certain limitations: Blackberry & Amazon Fire Users
Threema is not supported.
* If you are using Threema with an Android Wear smartwatch, you can read message previews, see chat pictures, agree/disagree to incoming messages and answer messages using dictation.
- Brazilian Portuguese
- Polish (Android only)
Threema for Windows Phone is only available in English and German at the moment.
If Threema is not available in the device’s system language, the user’s preferred languages (as defined in the system settings) will be taken into account (on Android 7.0 and on iOS). As a last resort, English will be used.
Threema offers the following basic features for both single chats and group chats:
- Send text and voice messages
- Share photos, videos, animated GIFs, and locations
- Send files of any type1
- Use Threema on the Desktop2
- Create polls1
- Silently agree or disagree to received messages
- Hide confidential chats and password-protect them with a PIN or your fingerprint2
- Choose between dark and light theme
- Use Threema on tablets and devices without SIM card
- Verify your contacts via QR Code
- Add text formatting to messages1
- Create distribution lists2
- Chat completely anonymously – no phone number required
- Contact sync is optional
- Quote text messages1
1 Currently not available on Windows Phone.
2 Currently only available on Android.
To test the features, you can use the ECHOECHO contact.
Threema also supports tablets and smartwatches.
Threema offers the unique feature of creating a poll right inside a chat. Forget about writing back and forth with your contacts when debating several options — initiate a poll with a few easy clicks and enjoy the useful overview about the voting process:
- Android: You can initiate a poll by tapping on the paperclip icon.
- iOS: Start a poll by tapping on the plus icon next to the text entry field.
- Windows Phone: Currently not available.
Have a look at an example in this video clip.
- In a single chat, tap and hold on a received message to invoke the context menu.
- To agree or disagree with the selected message, tap “agree / thumbs up” or “disagree / thumbs down”, respectively.
The agree/disagree feature is not supported in group chats.
On Android, set a PIN or enable Android’s Lock Screen (Android 6.0 and above) in Threema’s security settings. On iOS and Windows Phone, Private Chats are currently not available.
To mark a chat as private, long-tap on the chat, and then tap on in the title bar. When attempting to access the chat, you will be prompted to enter your PIN.
To hide all private chats, tap on the menu icon in the chat list, and choose “Hide private chats”. To show all hidden chats, choose “Show hidden chats” in the chat list’s menu, and enter the PIN.
On top of that, scanning someone's QR code is a convenient way of adding them to your contact list without having to manually enter their ID.
Launch the QR-code scanner here:
- Android: Side drawer > camera icon next to the QR code
- iOS: Threema > My ID > camera icon in the top right corner
- Windows Phone: Threema > “contacts” > QR-code icon in the toolbar at the bottom of the screen
If you are having trouble scanning a QR code, please make sure the camera is not too close (below 10 in/25 cm), which might prevent it from focussing.
To save a chat outside of Threema, you can export it as encrypted ZIP archive (which will contain the chat as text file and, optionally, all media files). Please note that exported chats cannot be imported into Threema again; to transfer your chats to another device (or to restore them later on the current device), use a data backup.
- Android: In the chat list, tap and hold a chat, and then tap the “Share” button. You can save or send the chat as an encrypted ZIP file using your installed apps.
- iOS: In a contact’s or a chat’s detail view, tap “Email Conversation”.
- Windows Phone: Regrettably, it is not yet possible to export a chat.
Use Threema to send files of any type (PDF, animated GIF, MP3, DOC, ZIP, etc.). Just like all other messages, files are end-to-end encrypted. On Android and iOS, the maximum file size is 50 MB; on Windows Phone, 20 MB. To avoid compression of an image or video, you can send it as file. Please note: If you send an image as file, its EXIF tags (possibly containing information such as the date and location the image was taken) are preserved.
Android: In a chat, tap on the paperclip icon, and select “File”.
iOS: In a chat, tap on the “+”, and select “Send file”. Due to restrictions of iOS regarding the file system, you can only access content of apps that support file sharing.
Windows Phone: Currently not available. Files cannot be received.
Threema is available in a light and a dark theme. You can switch between the two themes here:
Settings > Appearance > Design theme
Settings > Chat Display > Dark Theme
Threema respects Windows Phone’s system-wide color-scheme setting, which can be adjusted here:
Windows Phone > Settings > Start + Theme > Background
Colored chat bubbles can be toggled in Settings > Appearance > Colored Chat Bubbles.
To quote a text message, tap and hold it until the context menu appears. There, tap the quotation mark icon, and the quoted message will show up above the text input field. You can then compose and send your message like you usually would. In the chat, the quoted message is indented and prepended to your new message so that it’s evident what you are referring to.
On Windows Phone, this feature is not yet available.
Security and Privacy
Threema uses state-of-the-art asymmetric cryptography to protect messages between sender and receiver, as well as the communication between the app and the servers. Threema uses the Open Source NaCl library for encryption, which is open to independent audits. Anyone can validate Threema's correct application of the encryption.
There are two layers of encryption: the end-to-end layer between the conversation participants, and an additional layer to protect against eavesdropping of the connection between the app and the servers. The latter is necessary to ensure that an adversary who captures network packets (e.g. on a public wireless network) cannot even learn who is logging in and sending a message to whom.
All message encryption and decryption happens directly on the device, and the user is in control over the key exchange. This guarantees that no third party — not even the server operators — can decrypt the content of the messages.
Strength of the encryption: The asymmetric ECC based encryption used by Threema has a strength of 255 bits. Accordingto a NIST estimate (page 64), this corresponds at least with the strength provided by 2048 bit RSA. ECDH on Curve25519 is used in conjunction with a hash function and a random nonce to derive a unique 256 bit symmetric key for each message, and the stream cipher XSalsa20 is then used to encrypt the message. A 128 bit message authentication code (MAC) is also added to each message to detect manipulations/forgeries.Forward secrecy: Threema provides forward secrecy on the network connection (not on the end-to-end layer). Client and server negotiate temporary random keys, which are only stored in RAM and replaced every time the app restarts. An attacker who has captured the network traffic will not be able to decrypt it even if he finds out the long-term secret key of the client or the server after the fact.
For detailed technical information about the cryptography in Threema, read the Cryptography Whitepaper.
Many developers of messengers claim that their app encrypts the messages that users exchange. However, there are important factors to take into account:
Type of encryption
Other messengers: Transport encryption. With some messengers, only the connection between the user’s device and the server is encrypted, e.g. using SSL/TLS. Although this means that messages cannot be intercepted while in transit (a common problem in public wireless LAN hotspots), they are in unencrypted form again once they reach the server.
Threema: Full end-to-end encryption. Threema protects all messages using end-to-end encryption – not only messages in single chats but also group messages, files, and even profile pictures and status messages. A fallback to unencrypted or merely transport-encrypted connections is impossible. In addition, a separate transport encryption is used to protect the header information in transit.
Other messengers: Proprietary encryption technologies and algorithms. Some messengers use self-created encryption methods which aren’t established or which are controversial among experts.
Threema: Tried and trusted open-source encryption. Threema uses NaCl, a well-respected and widely used open-source encryption library. Using Threema’s Validation Logging, anyone can independently verify the correct application of the encryption.
Other messengers: No means of verifying contacts’ public keys. If there is no way for users to verify that messages are actually encrypted with a contact’s proper public key, a messenger is open to MITM attacks. The service provider could easily manipulate the automatic key exchange in order to read or forge messages without users noticing it.
Threema: Verification of contacts’ identities. With Threema, users can verify others’ identities by scanning their QR codes. This way, MITM attacks are prevented, and users can be sure that the key they’re using to encrypt messages to a certain user is actually the intended recipient’s public key, not someone else’s.
Other messengers: Unspecified key-pair generation. Key pairs (private key and public key) are the pivotal element of asymmetric encryption, yet many messenger providers don’t disclose how the key pairs are actually created. If key pairs are created and distributed by the service provider, the provider could keep a copy of the users’ private keys, which essentially means that there is a backdoor.
Threema: Local key-pair generation based on randomness. Threema’s key-pair generation is performed on users’ devices by means of randomness. The private keys never leave the users’ devices and remain unknown to Threema. Therefore, it is technically impossible for Threema to decrypt users’ messages.
Other messengers: Insufficient protection on users’ devices. Chats and files that are stored on users’ devices are protected only by weak encryption or are not encrypted at all.
Threema: Strong encryption on users’ devices. Chats and files that are stored on users’ devices are protected by strong encryption.
External security audits regularly review all security aspects of Threema, the used algorithms and protocols are well-documented, and the correct application of the encryption can be verified independently.
Comprehensive privacy protection requires solid message encryption, but there is more to it.
Threema can be used without providing any personal information whatsoever; linking a phone number and/or email address to your Threema ID is optional.
Optional contact synchronization
Synchronizing your address book in order to retrieve your contacts’ Threema IDs (provided they have linked them, see above) is optional. If you don’t want to grant access to your address book, you can either scan your contacts’ Threema IDs or add them manually.
In case you enable contact synchronization or link your ID with a phone number or email address, you can rest assured that Threema uses this information only temporarily for the specified purpose. Personal information is always hashed, both in transit and on disk.
All data involved in communication other than the actual content is metadata. Serious privacy protection must include both protection of content and protection of metadata. The sole protection of content is insufficient because metadata allows to uniquely identify individuals, analyze their behavior, determine their circles of friends, detect their frequent locations, and monitor their communication behavior. Combined with data from other platforms, the picture that can be drawn of a person is much more detailed than one that could ever be drawn from message contents alone. It’s likely that many messengers are used to systematically collect and analyze users’ metadata. Threema, on the other hand, generates as little data as technically possible and only stores it as long as absolutely necessary.
Plugins on Android
On Android, separate plugins are required in order to record and send voice messages and to use the QR scanner. If you don’t want to use these features, you don’t need to grant access to your device’s camera or microphone.
To learn more about the differences between Threema and WhatsApp in regard to privacy protection, please consult this comparison: The Threema Advantage
Using Threema ought to generate as little data on servers as possible – this is part of the concept. For that reason, data like e.g. contacts or group chats are stored in a decentralized way on user devices, instead of on a Threema server. Our servers assume the role of a switch; messages and data get forwarded, but not permanently stored. Where there is no data, there is nothing to be accessed or misused. However: without some kind of (temporary) data storage, there cannot be any asynchronous communication. In the following we will explain what kind of data we store, how we store it and for how long.
- Messages and group chats: As soon as a message has been successfully delivered to the recipient, it is immediately deleted from the server. All messages and media are transmitted end-to-end encrypted in Threema. This means: even if someone intercepted your message, it would be completely useless. Only the intended recipient is able to decrypt and read a message.
- No contact lists are stored when synchronizing contacts: The email addresses and phone numbers from your address book get anonymized (hashed) before they reach the server. Once the comparison is finished, they are immediately deleted from the server.
- Key pairs are generated in a decentralized way on your device. Your private key is never known to us, and therefore we cannot decrypt any message contents.
- Threema doesn't log who is communicating with whom (which Threema IDs are communicating).
Further information: Cryptography Whitepaper.
- Android: Threema includes its own app-specific encryption based on AES-256 to protect stored messages, media and your ID's private key. The key used for this encryption is generated randomly the first time you start Threema, and can optionally be protected by setting a Master Key Passphrase in the settings, which we highly recommend. Without a passphrase, the encryption will only add obscurity due to the way hardware encryption is handled on Android. If you set a Master Key Passphrase, you will have to enter it after every restart of the device (and after the system has terminated the app due to low memory).
Note: The PIN lock, which can be enabled independently of the master key passphrase, does not cause any additional encryption; it is simply a UI lock.
- iOS: Threema uses the iOS Data Protection feature to encrypt messages, images etc. in the device's flash storage. The key used for this encryption is linked to the device PIN. It is necessary to set a PIN in the system settings to use this feature. On newer models, iOS also uses hardware features for the encryption; therefore even a simple four-digit PIN offers a certain protection. For the highest protection against brute force attacks, you should choose a longer, more complex passcode.
Note: The passcode lock that is built into the app itself does not offer any additional encryption. This feature is intended to keep nosy people from reading your messages when you intentionally give them your phone for a short time for another purpose. Encryption with a four digit PIN inside the app would not be sensible, as brute force attacks would be trivial (since unlike iOS, an app cannot access special hardware features to protect the key).
- Windows Phone: Threema uses an isolated storage to which only Threema has access. Additionally, an app-specific encryption based on AES-256 is used to protect media files, ID, private key and messages. The key used by this encryption method is generated when the app is opened for the first time and can optionally be protected by a passphrase (which we highly recommend). A passphrase can be set in Threema’s security settings.
For detailed technical information about the cryptography in Threema, read the Cryptography Whitepaper.
Threema allows to verify that the ID of the person you are communicating with is really theirs.
If you are sure about your chat partner's ID, then there's no way for an attacker to spoof or intercept/decrypt a message from or to your chat partner.
The connection between the app and the servers is secure against MITM attacks because the server authenticates itself to the app based on a public key that is hard-coded into the app and whose corresponding secret key is only known by the legitimate servers.
Please note: Threema can only be as secure as the device that it is running on. Malware that runs in the background on your device can intercept and falsify data without being noticed. We highly recommend to always install the most recent operating system updates and to only use software from trusted sources.
That is your decision – Threema can be used without any address book access. If you have disabled the synchronization in Threema, no address book data will be read. You will then have to manually add your Threema contacts (by typing in their IDs or scanning QR codes).
If you decide to use the synchronization, email addresses and phone numbers from your address book will only be transmitted to the server in one-way encrypted (“hashed”) form and additionally protected using SSL. The servers only keep these hashes in volatile memory for a short time to determine the list of matching IDs, and then delete the hashes immediately. At no point are the hashes or the results of the synchronization written to disk.
Please note: due to the relatively low number of possible phone number combinations, it is theoretically possible to crack hashes of phone numbers by trying all possibilities. This is due to the nature of hashes and phone numbers and cannot be solved differently (using salts like for hashing passwords does not work for this kind of data matching). Therefore we treat phone number hashes with the same care as if they were raw/unhashed phone numbers.
All servers that are needed directly for the operation of the Threema app are located in Switzerland. Some auxiliary servers that only host public information, e.g. DNS servers, public websites or software download mirrors, may be hosted abroad for capacity and redundancy reasons.
In August 2015, Threema was subjected to an external security audit. The result confirms that Threema's concepts fully meet the requirements for secure and trustworthy instant messaging. Furthermore it attests that the implementation of all components relevant for security and privacy was performed properly as specified.
Read a summary of the audit report here.
A comprehensive Cryptography Whitepaper describing the algorithms and protocols used in Threema can be found here.
During initial setup of your Threema ID, a key pair for the encryption of messages based on Elliptic Curve Cryptography (ECC) is generated. This key generation is performed directly on your phone, without any server interaction. The private key never leaves your device. The random data necessary for key pair generation is obtained from the phone's random number generator and is mixed with further random data that you generate yourself by moving your finger on the screen. This ensures that even if a weakness is discovered in the phone's random number generator, the private keys of the users cannot be cracked.
For more information about the cryptography in Threema, read the Cryptography Whitepaper.
Show your friends and family members how convenient secure communication and privacy protection can be. The Threema Shop for Android and the iTunes App Store make it possible to give away Threema to your loved ones in just a few simple steps. On Windows Phone, it's currently not possible to gift apps.
- Purchase one or more licenses in our Threema shop (Google PlayStore doesn't offer a gift option).
- After succesful payment, you will receive an email containing the license key(s).
- Distribute the license to your presentee, for instance by email.
- Gift recipients can redeem the licenses here.
- New versions of the app can be automatically updated using the “About Threema” screen.
On your computer (in iTunes):
- Look up Threema in the App Store.
- Click on the downward-pointing arrowhead (“v”) next to the app's price tag.
- Tap on “Gift This App”, and follow the on-screen instructions.
On your iPhone/iPad:
- Look up Threema in the App Store.
- Tap the Share button in the navigation bar on the top of the screen.
- In the lower section of the Share Sheet that appears, tap on “Gift”, and follow the on-screen instructions.
Moving to a different operating system
Did you buy a new smartphone and switch to a new operating system (e.g., from iOS to Android)? In this case, you can maintain your Threema ID, but your chat history, contact list, and self-created groups can’t be transferred. Learn more.
Reinstalling Threema on the same operating system
Purchase via Google Play, App Store or Windows Phone Store
After resetting your phone or switching to a new phone, it may be necessary to reinstall Threema. The Apple App Store (iOS), Google Play Store (Android) and Windows Phone Store allow you to reinstall any purchased app at no additional cost. The only requirement is that you use the same store account (i.e., the same Apple ID, Google or Microsoft account) you used for the initial purchase. The store then will display an “Install” button instead of a “Buy” button. In case you still see a “Buy” button, please follow these instructions.
Purchase via Threema-Shop
If you have purchased the Android version in our store, you can download and then reinstall it with the same license key. If you have lost your license key, you can retrieve it. Please note: Threema versions from the Google Play Store are not unlocked using a license key, and you can't retrieve a license for a Google Play Store version. Because Google Play’s and the Threema Shop’s terms are not identical, licences can’t be transferred between the two sales platforms.
Paid apps are sold for a commission by different providers (Apple, Google, Microsoft). They neither share nor forward data about their customers and licenses. Hence it is impossible to move licenses from one platform to another. Hence, when switching between Android, iOS or Windows phone, the app has to be purchased again for the new operating system.
You can download a Threema version independent of all third-parties from https://shop.threema.ch.
Staying up to date: If Threema was downloaded from Google Play and automatic updates are enabled (in Google Play Store app > menu > Settings > Auto-update Apps), Threema updates will be installed automatically. If automatic updates are disabled, you can manually install updates in the Google Play Store app (by tapping the menu icon, navigating to My Apps > Threema and then tapping “Update”).
If Threema was downloaded from the Threema Shop, you will receive a notification in the app once an update is available. You can then install the update by confirming the notification. (You can also check for and install updates by navigating to “About Threema” > “Check for Updates” in the side drawer.)
Plugins for Android: In order to use the QR Code scanner or to record and send voice messages, you have to install the appropriate plugin (which will require permission to access the camera or the microphone, respectively).
iOS (iPhone, iPad, iPod touch)
Download Threema from the Apple App Store.
Keep Threema up to date by enabling automatic updates (in iOS > Settings > iTunes & App Store > Automatic Downloads > Updates), or update Threema manually in the App Store app (in the Updates tab).
Download Threema from the Windows Phone Store.
Keep Threema up to date by enabling automatic updates (in Windows Phone > Settings > Applications > Store > App Updates), or update Threema manually in the Store app.
To learn more about the current version’s changes and improvements, read the change log.
You can use Threema on multiple devices, however, currently only one ID per device is supported. Here's how you can send and receive messages on multiple devices:
- Tablet: Create a second ID for your additional device, e.g. a tablet.
- Tablet: Do not link this ID with your email address or your phone number. Use Surname/First Name-Tablet as the nickname for this device so it is recognized as such by your contacts.
- Tablet: Use your tablet to scan your smartphone's ID and save this contact as “My smartphone”.
- Smartphone: Scan your tablet's ID with your smartphone and save this contact as “My tablet”.
- Smartphone: Create a group with the contact “My tablet” and the ID of your chat partner.
- That's it. You can now have a conversation on all your devices, displayed as a group chat with your contact.
Please note: Two IDs cannot be linked to the same phone number or email, otherwise you would loose that connection of your current ID.
Consider also: Trouble with group chats - What can I do?
ID and Data Backup
Every user creates a unique, random Threema ID when setting up Threema for the first time. If you lose your smartphone or buy a new device, you need a backup of your Threema ID — without such a backup, certain contacts and your membership in group chats are lost. We recommend you to immediately create an ID backup after creating a new Threema ID.
When you switch your device or reset it to factory settings, you can transfer your Threema ID and use the app as usual. To transfer your ID, you need an ID backup. A data backup contains your ID, but it can only be used on the same operating system. For this reason, it’s recommended that you create an ID backup by following the instructions below. Please note that an ID backup doesn’t contain chats, media and your contacts' green verification levels. You can always export chats.
1. Backup your ID
- To create a backup, select the menu in the upper left and then tap on “My Backup”. Select the option “ID Backup” and choose a password. Make sure to memorize this password; without it, you will not be able to restore your ID.
- Your ID data (consisting of your private key) will be encrypted and shown to you as a text string and QR code.
- Save the backup of your Threema ID in a secure location. You can also send the information to yourself by email.
- You can include your ID backup automatically in your Android Backup.
- To create a backup, tap on “My ID” in the app, navigate to “Backup”, and choose a password. Make sure to memorize this password; without it, you will not be able to restore your ID.
- Your ID data (consisting of your private key) will be encrypted and shown to you as a text string and QR code.
- Save the backup of your Threema ID in a secure location. You can also send the information to yourself by email.
- You can include your ID backup automatically in the next iTunes/iCloud Backup.
- To create an ID backup, navigate to “Settings” and select “Backup”.
- Choose how to save your backup: on OneDrive, as text code or as QR code.
- Tap “Backup your Threema ID” and choose a password. Make sure to memorize this password; without it, you will not be able to restore your ID.
- Your ID data (i.e., your private key) is now encrypted and saved on OneDrive or displayed as text string or QR code.
2. Restore ID from Backup
- When starting Threema for the first time, select “Restore from backup” and follow the on-screen instructions.
- If Threema is already set up with another ID which you would like to replace, remove the current ID first:
- Android: In the sidebar, tap on your ID, then select “Delete ID”.
- iOS: In the tab bar, tap on “My ID”, then select “Delete ID”.
- Windows Phone: In the “My ID” tab, select “Delete ID”.
- Create an ID backup on your previous device: Tap on “My ID”, then on “Backup” and activate the option “Include in phone backup” at the end of the backup process.
- Create an encrypted iTunes backup. You can find the respective instructions on this Apple support page.
- Restore Threema on your new device from your iTunes/iCloud backup by restoring the iTunes backup of your previous device. Now you can resume using Threema as usual.
- Create a data backup on your old device: Navigate to “Settings” and select “Backup”.
- Tap on “Create Threema data backup” (this will replace any previous backup). Your data is now saved to OneDrive.
- It is recommended that your device is plugged in and connected to a WiFi network during backup. Otherwise, the following limitations apply: Without WiFi connection, no more than 5 MB can be transferred. Without external power supply, no more than 20 MB can be transferred to OneDrive. (With both a WiFi connection and external power supply, the backup size is limited to 100 MB).
- Install Threema on your new device and launch it. Tap on “or tap here to use an already existing backup”.
- First, restore your ID backup. Then, tap on “Recover from OneDrive” and enter your password. Your Threema data is now being restored. Please be patient.
- It is recommended that your device is plugged in and connected to a WiFi network during the restore process.
To restore a Threema ID, you need an ID backup. It consists of 80 digits and letters in groups of four characters (separated with dashes). You will get this string in two formats after creating an ID backup: as plain text for copying/pasting, and as a QR code.
In the restore menu, you can either enter the long string manually, or you can scan the QR code. Restoration is only possible with an ID backup. If you mistakenly scan a public Threema ID, you will see a long string after scanning that starts with “3mid:”. Restoration will not be successful in that case. Please ensure that you are using an ID backup for restoration.
We have no access to your data. If you would like to restore your ID, messages or contacts, you need both a backup and the associated password. If some of the information is missing, your data is not accessible anymore. We can provide you with the following general recommendations:
- Ask your chat partner if he or she can send you the messages/media files once more, or if he or she can export the conversation as a text file.
- Adjust Threema's settings to automatically save incoming media files to the standard media folder of your operating system. This will keep these files accessible to you even if you delete the app.
- Create a PIN lock for your app, e.g. to protect your ID in case of theft of your device.
Verification of the email address
Emails might get stuck in spam filters, so please check your spam folder, and please be patient. Some ISPs use greylisting, which causes emails from new senders to be delayed by up to an hour.
You can try again (perhaps using a different email address) by going back to the “Linked Email” dialog, clearing the address and saving. This will reset the status, and you will be able to try again.
Verification of the phone number
We make a best effort to deliver text messages to all countries. If you don’t receive the verification message, this might be due to a temporary problem or because your carrier filters certain messages. Threema offers the option to request the verification code via a phone call:
- On Android, a green banner is displayed on the main screen during pending verification; tap “Enter Code” and then “Request call”. Please note that a phone call can only be requested after the SMS reception timeout (of approx. one minute) has elapsed.
- On iOS, simply go back to the “Linked Number” dialog and choose the call option.
Please understand that we cannot call certain countries/numbers.
Note: You can use Threema while the email verification and/or the SMS verification is pending. You can also choose to use Threema without providing a phone number and email address. In this case, however, others need to know your ID in order to contact you.
Remove Threema ID from current device
Would you like to remove your Threema ID from the current device in order to create a new ID or to restore a backup? Delete your ID in the “My ID” section (on Android, “My Threema ID”) in the Threema app. (On Android, tap the menu icon in the upper left corner of the main screen, and then tap on your ID to get to the “My Threema ID” section.) When starting Threema the next time, you can use the setup wizard to create a new ID or to restore a backup.
Please note: When deleting your Threema ID as described above, the ID will only be removed from the current device. In case the ID also set up on another device, it will not be deleted there. Also, the deleted ID can still be restored if a backup was created.
Permanently delete your Threema ID
If you should ever happen to lose access to the device on which your Threema ID is set up (e.g., if the device is stolen), you can revoke your ID only if an ID revocation password was set. Set an ID revocation password here:
- Android: menu icon > your ID > “ID Revocation”
- iOS: “My ID” > “ID Revocation Password”
- Windows Phone: Currently not supported.
Without access to your ID or without a previously set revocation password, it is not possible to delete the ID. However, the ID will be marked as inactive automatically after three months of inactivity.
If you revoke your ID, other users will be unable to send messages to this ID after about one hour. Within 24 hours, the ID will be crossed out (or hidden, if Hide Stale Contacts is enabled) on your chat partners’ contact lists.
In contrast to other messengers, your identity in Threema is not dependent on a phone number. Irrespective of the SIM card / phone number you're using or in which country you are, your Threema ID stays the same and everyone can still reach you. Your existing chats are unaffected by a change of your phone number as well.
Do you have a new phone number and don't want to use the old, linked one anymore? Simply delete the old number on the “My ID” tab and type in the new one — your ID is now linked to the right number.
If you link your new Threema ID to the same phone number or email like the previous ID, your contacts might see your name twice. You can fix this as follows:
- Link your new ID with the same email address and phone number as your old ID. This will cause the link of the old ID to be removed, since every email address or phone number can only be linked to one ID at a time.
- Ask your chat partners to delete your old ID from their contact list. It will not be found during synchronization anymore as the links have been removed.
If you cannot or prefer not to create a new ID, you can also unlink your old ID.
Read here how you can get rid of duplicate contacts in your own address book.
Sending / Receiving
- Message sending
The message is being sent to the server. If this status lasts for more than a few seconds, there might be a connection problem. In this case, the message will stay in queue and will be sent as soon as the connection is up again (on iOS and Windows Phone, only when the app is open).
- Message sent
The message was successfully delivered to the server, and a push notification was sent to the recipient if necessary. For technical reasons, if the recipient uses iOS or Windows Phone, this status lasts until they open the app (regardless of receiving a push notification). If the recipient has disabled read receipts, this status is permanent and persists even if the message was delivered or read.
- Message delivered
The message was successfully delivered to the recipient's device; it has not yet been opened by the recipient, but a preview was displayed. For technical reasons, if the recipient uses Windows Phone, this status is only displayed once the recipient opens the app (not when the push notification is shown). For messages to recipients with iOS, this status is displayed immediately after delivery if the recipient has enabled push preview; otherwise the status will only be shown when the recipient has started the app. If the recipient has disabled read receipts, this status will not be displayed.
- Message read
The message has been read by the recipient. If the recipient has disabled read receipts, this status will not be returned.
- Sending failed
The message could not be sent. This can happen, for example, when the network connection is interrupted during a file transfer. You can tap and hold on the message and then choose “Forward” (Android) or “Try again” (iOS) or “Send” (Windows Phone).
- / User agreement/disagreement
The recipient agrees/disagrees with your message. (Learn more about the agree/disagree feature here.)
The recipient can disable read receipts in Threema settings (privacy).
Note: due to technical reasons, messages to recipients with Windows Phone, or iOS with disabled push preview, will only show the status “delivered” or “read” when the recipient has opened the app to read the message. However, the push notification that informs the recipient about the new message should still appear within a few seconds (typically).
A colored stripe at the navigation bar or a small dot next to the Threema logo shows the connection status at a glance.
- Red: Threema is currently not connected to the server. This is usually due to problems with the Internet connectivity of your phone (e.g., when you have no 3G reception or if you are connected to a broken Wi-Fi network or to a Wi-Fi hotspot that requires login). Threema will keep trying to establish a connection every 10 seconds.
- Orange: Threema is connecting to the server. A response has been received (i.e., a connection has been established), but the login process has not completed yet. If this status persists for more than a few seconds, it's usually due to a slow or unstable Internet connection.
- Green: Threema is connected to the server. New messages will appear instantly.
- Android: You can insert emoji via the menu next to the text input field. Third-party emoji-keyboards are not necessary.
- iOS: Unicode emoticons are handled by the system. Go to Settings > General > Keyboard > Keyboards, and activate the “Emoji” keyboard. After that, you can switch to this keyboard while you're typing by tapping the globe symbol.
- Windows Phone: On the regular keyboard, tap the smiley key (next to the spacebar) to invoke the emoji keyboard.
On Android (all app versions) and iOS (Threema version 2.9.0 and up), incoming messages can be decrypted in the background and presented along with a preview in the push notification. Push preview must be enabled in Threema settings for the preview to be shown.
If there is no Internet connection immediately after a push notification has been received, it is possible that no preview can be shown.
No preview will be shown on Android if:
- the master key is locked, or
- PIN protection is activated, or
- background data is restricted
A sender's name (as saved in the contact list) is not visible in push notifications on Windows Phone due to technical limitations of the operating system. On iOS, contact names will only be displayed if the push preview setting is enabled.
In all other cases, the “public nickname” is displayed instead. By default, it assumes the value of the user's ID, but can be changed anytime. You can ask the sender to use e.g. his or her first name. This will help you recognize the sender of a message.
Problems with sending messages can have different causes. Please proceed as follows:
- Please send a message to the ID ECHOECHO. If this works and you receive a response, you're fully able to send and receive messages, and the problem is most likely on the recipient's side.
- Make sure that the Threema ID displayed for the contact you want to reach is still actively used by the recipient. The latter might be using a new ID, in which case messages to the old ID are being misrouted. This can easily be prevented by deleting old IDs and removing duplicate contacts.
- Maybe your ID has been unintentionally blocked by the recipient. Ask the recipient to check this in your own contact's details (iOS: Contacts > Contact details > “Block contact” (at the very bottom); Android: Threema > Contacts > Tap and hold on the contact > Settings > “Deblock contact”). Please also make sure that you have not blocked the recipient yourself.
There is a special ID named ECHOECHO that simply echoes back all messages that you send to it. Here is the QR code that you can scan to verify its key:
Note that in general, QR codes for ID verification should not be sent over the Internet but only scanned from the personal mobile phone of the respective person in order to ensure that there has been no manipulation by third parties.
Threema uses Google Cloud Messaging (GCM) only to inform the app in the background about incoming messages. The app then fetches messages directly from the Threema servers. Neither contents nor details about messages are transmitted via GCM (the GCM payload is empty).
You can choose whether or not you would like to use Threema with Google Services. The option “Troubleshooting > activate Polling” allows you to use Threema without GCM. However, we don't recommend this.
The development of a custom push-service is difficult, since its reliability depends on numerous factors. We are therefore consciously using the recognized push services of Apple, Google and Microsoft. They are already installed on the vast majority of devices. Furthermore, channelling push notifications saves battery power.
Messages and media are stored on the servers until they have been delivered successfully, or until 14 days have elapsed (whichever happens first).
Block single users
If you receive unwanted messages from another Threema user, you can block them:
- Android: Long-tap the contact in the contact list and open its details. Open the menu and choose “Block contact”.
- iOS: Tap the contact in the contact list and scroll down to the option “Block contact”.
- Windows Phone: This feature is currently not available.
A blocked contact doesn't see if he or she is blocked.
Threema allows you to block messages from unknown users in general. You will find this option in “Threema > Settings > Privacy > Block unknown”.
Please note: When the option “Block unknown” is on, you might not receive messages from your friends if you didn't save their details in your address book or if they didn't link an email address or phone number to their Threema ID. This could make them believe that the sending of messages isn't working properly.
Specific contacts can be excluded from your contact list by using “Threema > Settings > Privacy > Exclusion list”.
Everything you send with Threema is encrypted before sending. This can require a high processor load, especially on older devices. We strive to provide both security and performance to all our users independently of their devices, which is why the sending of videos is currently possible within the following limits:
Android: Irrespective of its duration, the video's file size cannot exceed 50 MB. If you are using Android 4.3 or higher, you can compress videos in Threema > Settings > Media, allowing you to send even very large files, depending on the compression type.
iOS: Videos in high quality can be up to three minutes long; in low quality, videos can be up to 15 minutes long.
iOS: If you prefer to not receive push notifications for incoming messages of a certain contact, open the contact’s detail view (by tapping the contact in the contact list), and enable “No push notifications”. Notifications for group chats can only be adjusted globally at the moment (in Settings > Notifications > Push Notifications > Group Notifications).
Windows Phone: Currently not available.
You will still receive messages in muted chats, but you will no longer be notified about them by push notification (meaning that you have to manually open the app in order to see whether any new messages were sent in muted chats).
Threema transmits messages via the Internet. Aside from Internet connectivity charges (which may vary depending on the mobile network provider), there are no other fees per message.
A group chat feature (up to 50 group members) is available in the app. Group chats are handled on each individual device. The Threema servers have no knowledge about group compositions.
New groups can be created using the “Compose message” button (iOS), or using the menu item “New group” (Android) and “New group chat” (Windows Phone). Only those contacts can be selected from the list that have installed a group chat capable version of Threema.
As group administrator, you can delete a group at once, without having to remove all members manually. Please note: After you have deleted a group, other group members can’t use it anymore, but the group messages will not be deleted. To delete a group, open it, tap on the group’s name in the title bar, open the menu and select “Delete group”,
As a regular group member, you cannot delete a group, but you can leave it. Please note: When leaving a group, the group messages will not be deleted. To leave a group, open it, tap on the group’s name in the title bar, open the menu and select “Leave group”.
To remove the chat from your chat list and delete the chat history, tap and hold the chat, and then tap the trash-bin icon.
Groups created by an iOS or Windows Phone user are deleted as soon as the last member has left the group.
To leave a group on iOS, swipe over the group from right to left (in the chat list or in the group list), and tap “Delete”.
Groups created by an iOS or Windows Phone user are deleted as soon as the last member has left the group. To leave a group, open the group’s chat, and navigate to “...” > “Group Info” > “...” > “Leave group”.
Yes. If you are a group admin, you can add members or remove them from the group chat.
Like single chats, group chats are end-to-end encrypted in Threema. For privacy reasons, groups are not managed on our servers but directly on users’ devices. Since there is no information concerning group compositions stored on the server, groups can become asynchronous, e.g., if a user restores a backup or is absent for an extended period of time.
If a group is asynchronous, we recommend resynchronizing it first. Only the group administrator can initiate a synchronization (in the group's detail view). Should the problem persist, please remove the group member due to which the group became asynchronous (see above), and add them again.
You can access a group's detail view as follows:
- Android: In the group chat, tap on the title bar.
- iOS: In the group chat, tap on the title bar, and then tap on the bar that appears underneath it (containing tokens of the group members).
- Windows Phone: In the group chat, tap on “…”, and then tap on “group details”.
If some members cannot see messages in a group chat, it is usually because they have activated the option “Block Unknown”. Disable the “Block Unknown” option in Threema > Settings > Privacy to receive all group-chat messages.
For privacy reasons, groups are not managed on our servers but directly on users’ devices. Therefore, an ID backup will not suffice to restore groups.
After restoring an ID backup, groups you have not created yourself will appear once other group members have been active. Groups which you have created yourself, on the other hand, can only be restored using a data backup.
As data backups cannot be used when switching operating systems (e.g., when moving from Android to iOS), you will have to recreate on your new device the groups you initially created on your old device.
Like single chats, group chats are end-to-end encrypted in Threema. For privacy reasons, groups are managed in decentralized manner on users’ devices, not on a server. Neither is it possible to transfer administrator privileges, nor can administrator privileges be granted to multiple users.
Cloning groups (Android)
If a group’s administrator leaves the group, a new group must be created. On Android, groups can be cloned. If a group member clones a group, they become administrator of a new group consisting of the same members as the initial group. However, the chat history is not transferred to the new group.
To clone a group on Android, tap the title bar in the group chat, then tap the three vertical dots, and select “Clone group”.
The dots are an indicator for a contact's verification level. They don't affect the encryption strength, but are a measure for the probability, that the saved public key of a contact belongs indeed to that contact.
- Level 1 (red): the ID and public key have been obtained from the server because you received a message from this contact for the first time or added the ID manually. No matching contact was found in your address book (by phone number or email), and therefore you cannot be sure that the person is who they claim to be in their messages.
- Level 2 (orange): the ID has been matched with a contact in your address book (by phone number or email). Since the server verifies phone numbers and email addresses, you can be reasonably sure that the person is who they claim to be.
- Level 3 (green): you have personally verified the ID and public key of the person by scanning their 2D code. Assuming their device has not been hijacked, you can be very sure that messages from this contact were really written by the person that they indicate.
The verification levels don't change anything in the encryption strength (it is alwaysthe same high-grade ECC based encryption), but they are a measure of thetrust that the public keys saved for your contacts really belong to them. Having the wrong public keys leaves you open to man-in-the-middle (MITM) attacks, therefore it isimportant to verify the keys.
Threema displays only contacts who use Threema. If you know that someone is using Threema, but he or she is missing or marked with the verification level 1 (red), it is because of one of the following reasons:
- Your contact has not linked his or her Threema ID with a phone number or email address.
- Your own address book contains neither your contact's phone number nor email address.
If both of these conditions are met, and if synchronization is enabled, any contact found during the synchronization process is automatically added to your Threema contact list and marked with verification level 2 (orange).
To start the synchronization process, simply tap on your contact list, drag it down and release it again. To work properly, activate the synchronization feature in Threema > Settings > Privacy. If you are an iOS user, make sure to grant Threema access to your contacts (iPhone Settings > Privacy > Contacts > enable Threema).
In your contact list, inactive IDs are greyed out (contacts that haven't been active for more than three months). As soon as they resume using Threema, they appear as active contacts again (within 24 hours).
In a group chat, only contacts that are running a group chat capable version of Threema (and who have started it at least once since the update) can be selected.
You can get rid of duplicate contacts by activating the option “Hide Stale Contacts” (Threema > Settings > Privacy). Stale contacts are IDs that haven't been used for more than three months. Therefore, it might take a while for contacts to be marked as inactive.
Alternatively, you can delete every contact that is listed multiple times. After each deletion there will be a question whether you would like to exclude the respective contact from future synchronization processes. Please decline that option every time. After you synchronize your address book again, only active contacts (Threema IDs) will be displayed.
If the contact has been synchronized with the device's address book, simply change the name in the “People/Contacts” app. After the next synchronization in Threema (can be forced by pulling down and releasing the contact list), the new name will be used.
The name of unsynchronized contacts can be changed in the contact details:
- Android: Tap on the pencil icon.
- iOS: Tap on “(i)”.
- Windows Phone: Tap on the box “contact name”.
The Threema Channel features several feeds for different topics. You decide which feeds you want to subscribe to, and you can cancel subscriptions at any time.
To add the Threema Channel, simply add the ID *THREEMA to your contact list, either manually or by scanning the following QR code:
Then, send the keyword “info” to the Threema Channel to get a list of available feeds and subscribe to the ones you like. Enjoy!
- Open the side drawer (by tapping on “≡” in the app’s main view), and tap “My Threema ID”
- First, tap the pencil icon; then, tap the avatar icon (or the current profile picture if one is already set)
- Choose between “Take photo” and “Select from gallery”
- Crop the image you have selected, and confirm by tapping “Save image”
- To choose who is allowed to see your profile picture, tap “Release profile picture to”
- Navigate to the “My ID” tab, and tap on “(i)”
- Tap “Pick image” (or tap the current profile picture if one is already set), and select an existing picture, or snap a photo
- Crop the image, and confirm by tapping “Choose”
- To choose who is allowed to see your profile picture, tap “Release profile picture to”
- Windows Phone
- In the app’s main view, navigate to the “my Threema ID” tab, and tap the avatar icon (or the current profile picture if one is already set)
- Select an image, crop it, and confirm by tapping the checkmark at the bottom right
- To choose who is allowed to see your profile picture, tap “Release profile picture to”
For privacy reasons, profile pictures are not stored on a server, they are transmitted between users upon message exchange and are end-to-end encrypted.
The next time you send someone a message, your profile picture will be transmitted automatically (provided your settings allow it). Alternatively, you can transmit your profile picture manually to a contact by tapping “Send profile picture now” in the contact’s detail view.
If a contact has disabled profile pictures, your profile picture will not be displayed in their contact list and chat overview.
To remove your profile picture, proceed as follows:
- Open the side drawer (by tapping on “≡” in the app’s main view), and tap “My Threema ID”
- Tap on “⋮” in the top right corner, and select «Remove image»
- Navigate to the “My ID” tab, and tap on “(i)”
- Tap on your current profile picture, and select “Delete Photo”
- Windows Phone
- In the main view, navigate to the “my Threema ID” tab
- Tap and hold your current profile picture, and select “remove profile picture”
For privacy reasons, profile pictures are not stored on a server. The next time you send someone a message, your profile picture will be removed automatically on the recipient’s end. Alternatively, you can immediately remove your profile picture from someone’s contact list by tapping “Send profile picture now” in the contact’s detail view.
Should you prefer to use your own contact pictures (or if you wish to not display contact pictures at all) instead of the profile pictures your contacts have set for themselves, navigate to Settings > Appearance, and deactivate “Show profile pictures”.
If “Show profile pictures” is enabled, your contacts’ profile pictures are displayed no matter if you have set contact pictures for them in Threema or in your operating system’s address book.
If a contact picture is set for a contact in Threema or in your operating system’s address book, this picture will only be displayed in Threema if “Show profile pictures” is deactivated or if the contact in question hasn’t set a profile picture (or doesn’t share it with you).
If (for some contacts) no profile pictures are displayed in the chat overview and in the contact list, this might be due to one or more of the following reasons:
- Profile pictures are disabled (in Settings > Appearance)
- The contacts in question haven’t set a profile picture, or they don’t share it with you
- The contacts in question didn’t send you a message since setting their profile picture (profile pictures are transmitted upon message exchange)
- Windows Phone: The chat partners in question are not saved in your contact list (in the chat overview, only profile pictures of chat partners saved in the contact list are displayed)
Threema uses Google Cloud Messaging (GCM) to wake up the phone when new messages arrive. This way, the app does not have to stay connected to the Threema server in the background all the time (which would cause additional battery drain). After one minute in the background, the connection to the Threema server is disconnected, and the server informs the app via GCM when new messages arrive.
Please check whether you have disabled notifications, muted a chat or banned a contact by mistake.
- Android 5 and later: Device settings > Sound & notification > App notifications > All apps > Threema > “Block all” has to be disabled, “Treat as priority” enabled
- Open the affected chat in Threema.
- In the menu, choose “Notification settings”, and make sure the chat is not muted and “Disable notifications” is deactivated.
- In the menu, check whether “Unblock contact” is present; if so, select this option.
In order for Threema to receive notifications, the device has to be online.
- First, reboot your phone.
- Make sure Wi-Fi is kept on during sleep: Android Settings > Wi-Fi > Advanced > Keep Wi-Fi on during sleep > Always
- Please never quit Threema with an App Manager (force quit). You will not get any notifications until you reopen the app.
- Go to Android Settings > Data usage, press the menu button and ensure that “Restrict background data” is disabled.
- In this menu also tap on Threema and make sure that the “Restrict background data” option is disabled there too. Also check this for the Google Play services.
- In case you are using system tools like Battery-Saver, Juice Defender, Antivirus, PrivacyGuard, xPrivacy or similar, please deactivate these tools temporarily or make sure they do not interfere with Threema.
- Please make sure you are using the most recent version of the Google Play Services and update them if needed.
- In case you have updated your phone's operating system, you need to reinstall the app.
- Make sure your phone's battery saving mode is turned off.
- Android 6 and later: Android Settings > Battery > Battery optimization > All apps. Scroll to Threema, and select “Don’t optimize”.
- Sony: Disable “Stamina” mode
- Huawei: Go to Huawei's “Phone Manager” > Energy Saver > Protected Apps and mark Threema as a protected app.
- Xiaomi / MIUI: First, navigate to “Settings > Additional Settings > Battery and Performance > Manage apps’ battery usage”, and turn “Power saving modes” off. Then, open the Security app, navigate to Permissions, and add Threema to Autostart. Finally, summon the Task Manager, find Threema, and drag it downwards until the padlock icon appears.
Should the above suggestions not solve the problem, please follow the steps below:
- Make sure you have deactivated the polling option in the troubleshooting section of the Threema settings.
- Reset the GCM push token in Threema (Settings > Troubleshooting > Reset push token).
Please note that a delay of a few minutes is normal on Android 6 or later if your phone has not been moved for a certain amount of time. This is due to Android’s Doze Mode, which significantly reduces power consumption during standby.
Threema runs on Android 4.0 (Ice Cream Sandwich) and up.
Here is an explanation of the most important permissions that Threema for Android requires:
- Read/write contacts
Required for address book synchronization. If the synchronization is off, contact data is not accessed.
Used for the “Send location” feature.
Used for contact synchronization resp. integration into the account management of Android.
- Storage ("SD card")
Used for saving media data (photos, videos).
Yes, that is possible if you buy Threema from our own shop.
Please note: no Google Account is necessary, but Google Apps need to be installed on the device because GCM is used for push notifications. Google Apps are always included in original manufacturer firmwares; they may have to be installed separately in custom ROMs (CyanogenMod etc.).
This problem only affects the Android version of Threema under specific versions of the Android operating system.
Some Android versions (Jelly Bean 4.1.1 is usually affected, and on some Samsung devices even more recent versions) have a bug that affects paid apps. The sync account is lost after rebooting the phone; consequently, the contact synchronization does not work anymore. We're currently searching for a reasonable workaround and recommend all users to update to a newer operating system version if possible.
As a temporary solution, you can turn the synchronization off and on again in the Threema settings. This will cause the account to be recreated and the synchronization will work again until the next phone reboot.
More information on this Android bug can be found here.
You might be experiencing issues with Threema after upgrading your phone's operating system or making other changes to your phone. In such a case it might be necessary to reinstall the app. To avoid a losing your data, please follow the steps below:
- Create a data backup in Threema including media files (find out how).
- Go to Android > Settings > Apps > Threema.
- Tap on “Delete data” and uninstall the app. Do the same for Threema's plugins.
- Reboot your phone and reinstall the app and the plugins.
- Open Threema and restore the previously created backup with our setup wizard.
Did you purchase Threema in the Google Play Store, but can't see updates or an install button in the Google Play Store? Please proceed as follows:
- Make sure you are using the same Google Account as when you purchased Threema.
- On your computer, log into play.google.com. Click on the settings icon in the upper right corner and then on “My Account”. Does Threema appear in your order history?
- If you can see Threema, please delete the data of your Google Play Store and Download Apps on your phone according to these instructions.
- Restart your phone and log in to the Google Play Store. You can now proceed with the update or reinstallation of Threema.
- If Threema is not listed in your order history, you were using another Google Account when you purchased Threema, or you bought it in our own shop.
Android automatically quits background tasks if you are low on memory space. This might affect a process which is responsible for keeping the passphrase present in memory. You must re-enter your passphrase when starting up Threema. Threema cannot change this.
If you are frequently asked to provide your passphrase, we recommend you to disable it and use global encryption on your device instead. You can find this in your phone's settings: Security > Encrypt phone or Security > Encrypt device.
This notification is shown if you're using the Android version of Threema and have set a passphrase on your master key. In order to prevent the operating system from terminating the Threema process (which would cause the unlocked master key to be lost as it is only held in RAM, necessitating manual re-entry of the passphrase), the app needs to show a notification. This notification has no other purpose and is only required because of the aforementioned limitation of Android.
Please note: in times of extreme memory shortage, Android will even terminate processes that show a persistent notification. In that case, it is possible that you are prompted for the master key passphrase again. This is caused by Android; Threema has no influence on this process termination.
In version 1.2, a new PIN lock feature has been introduced (can be enabled in settings), which is much better suited to use as a user interface lock, and easier to use than the master key passphrase. The master key passphrase is therefore now only intended as protection against offline attacks, for which a one-time prompt after a device reboot is sufficient.
If you set up a PIN, the lock button will reappear in the action bar and can be used for manually activating the PIN lock.
Long-tap the desired media in the chat, and then choose “Save” (floppy disk icon). The saved media can be found inthe directory “Threema/Threema Pictures” (or “Threema Videos”, “Threema Audio”).
This backup option uses Google’s “Auto Backup for Apps” to periodically create encrypted backups on Google Drive. The following data is saved:
- ID and key pair
- Contacts and verification levels
- Group memberships
- Contact and group images
- All settings
Please note that media files are not saved.
Backups are created about every 24 hours, provided the device is idle and connected to a Wi-Fi network and an external power source. The exact time is determined by the operating system based on various parameters. Threema can’t initiate the backup process. In some cases, it can take several days until a backup is created. There is no way to manually trigger the backup process.
In the “Android Backup” tab, the status is “pending” until the first backup is created; then, date and time of the latest backup will be displayed. To get a list of all backups, open the Google Drive app and navigate to “[side drawer] > Backups > [device name] backup > Apps > Threema”.
Backups are encrypted using NaCl and stored on Google Drive. It’s not possible to store backups in a different location. Since the symmetric key is derived from the password, it’s particularly important to choose a strong password. For more information about encryption, please consult the Cryptography Whitepaper.
If Android’s “Automatic restore” is enabled (in “Settings > Backup & reset”), the latest backup will be automatically restored after the app was installed on a new device (or reinstalled on the current device), provided the same Google account is used. When opening the newly installed app, the user is prompted for the password, and once the correct password is entered, Threema restores the latest backup and restarts.
Differences between “Android Backup” and data backup
When using “Android Backup”, backups will be created on a regular basis without any user interaction, whereas the creation of data backups must be manually triggered by the user. Hence, there is always a current backup available when using “Android Backup”. This is a key advantage of “Android Backup” over data backups. Furthermore, app settings are included in “Android Backups” (but they are not included in data backups). On the other hand, data backups can include media files, while “Android Backups” don’t include media files because Google limits the backup size to 25 MB per app and user.
On Android, distribution lists can be used to send messages to multiple recipients. In contrast to group chats, messages are sent to the recipients separately when using distribution lists. Thus, the recipients are unaware of the fact that other recipients have received the same message. Sending a message to a distribution list is essentially the same as sending the message to each member of the distribution list in a single chat.
To create a distribution list on Android, proceed as follows:
- In the chat overview, tap the floating action button (labeled “+”) in the lower right corner, and choose “New distribution list”
- Select the recipients who shall receive messages sent to this distribution list, and conclude your selection by tapping the check mark in the top right corner
- Specify a name for the distribution list, and confirm by tapping “OK”
If you have accidentally answered “No” when you were asked whether you want to allow Threema to access your photos, you can grant permission as here:
If Threema isn't listed, navigate to iOS Settings > General > Restrictions > Photos, select “Allow Changes”, and make sure the switch next to Threema is enabled. After adjusting these settings, try again sending an image in Threema.
Please perform the following steps to troubleshoot push notifications on iOS:
- Ensure that push notifications for the affected contact are not disabled (go to contact details in Threema, scroll down and make sure the “No push notifications” option is turned off).
- Go to iPhone Settings > Notifications > Threema. Ensure that badges, alerts and sounds are turned on.
- Turn off your phone.
- Turn your phone back on.
- Open Threema so it can re-negotiate push notifications with the server.
- Push notifications should now be working.
Also make sure you're not connected to a Wi-Fi network that blocks the ports that Apple uses for push notifications (try turning off Wi-Fi to see if this makes push notifications work).
If you still cannot receive push notifications even after following the steps above, try deleting and reinstalling the app from the App Store as a last resort (you will not be charged again). By reinstalling, the so-called push token that the iOS system generates for the app is recreated. Your Threema ID will be retained, but the contacts and any saved messages in the app will be lost (don't forget to re-enable contact synchronization in Settings > Privacy after reinstallation if desired).
There are two ways to share files using Threema on iOS.
Select the files in Threema: In a conversation, tap the plus sign (“+”) next to the input box, and select “Share File”. Then, choose the app that hosts the file you would like to share (e.g. Contacts), select the file, and confirm by tapping “OK”.
Select the files in another app: In the app of your choice, select the file you would like to share, tap the Share Button, choose “Open in Threema” (depending on the app, you might need to tap “Open in…” first), select the contact you would like to send the file to, and confirm by tapping “Send”.
The latest version of Threema supports iOS 8 and up. You can continue to install or use older Threema versions on your pre-iOS 8 device, but you won't be able to update to newer versions.
Here are the last supported Threema versions for each iOS release:
- iOS 5: Threema 2.4.3
- iOS 6: Threema 2.5.0
- iOS 7: Threema 2.6.2
If you have not bought Threema before, but would like to buy and install it on a pre-iOS 8 device, you need to first use iTunes on a Mac or a PC to buy Threema. Then, using the same Apple ID on your pre-iOS 8 device, go to the App Store and download the already purchased app. You will be asked whether you want to install the last compatible version.
The effort needed to offer compatibility with older iOS versions is substantial. Apple doesn't provide a means to test working order and reliability of new app versions on old iOS versions. For this reason, we need to drop support for older iOS versions from time to time when we release larger updates.
If push preview is enabled, Threema for iOS (app version 2.9.0 and up) will become active in the background when a push notification arrives. It downloads the message from the server, decrypts it and shows the decrypted content in the push notification. Apple does not receive any other data than when push preview is disabled; the decrypted contents remain exclusively on your own device.
In order for the Threema app to decrypt messages in the background, it needs continuous access to the message database and the private key. If push preview is disabled, this data is protected using iOS Data Protection mechanisms such that it is only available when the iPhone is unlocked (so-called “NSFileProtectionComplete”). If push preview is enabled, the security level is reduced such that the database and the private key are accessible continuously after the first unlock of the iPhone following a reboot (so-called “NSFileProtectionCompleteUntilFirstUserAuthentication”). In practice, this does not make much difference, as one still needs to enter the device PIN or fingerprint to access the app. For the highest security and to avoid that the keys which protect the message database and the private key are present in the device's memory even when it is locked, the push preview can be disabled.
Irrespective of this, disabling push preview prevents passersby from reading message contents from the lock screen of a device that has been left lying around.
Group chats are fully supported on Threema for Windows Phone. You can become a group member, create and administer a group on Threema 1.3.1 and higher.
Probably this behaviour is caused by a problem with the push notification service. Please proceed as follows:
- Reboot your phone.
- Allow Threema to run in the background when battery saving mode is enabled or make sure that battery saving mode is not activated.
- Check the notification settings for Threema in your phone’s settings.
Should the problem persist, please try the following:
- In Settings > Location, toggle Location Services.
- In Settings, toggle “Find my phone”.
- Reboot your device.
Threema Web is Threema’s web client. With Threema Web, you can use Threema on the desktop without compromising security. You have full access to all your chats, contacts, and media files. Threema Web is open source.
Once web browser and mobile device are connected, you can use Threema in your browser just like you use Threema on your mobile device. Threema Web acts as extension of the Threema app and meets the high security standard Threema is known for.
Threema Web establishes a direct connection between desktop and mobile device (if both devices happen to be present on the same network). This way, no server is involved when synchronizing messages between the devices, and the digital footprint is reduced to the bare minimum.
Make sure you are using the latest version (3.0 or above) of Threema. Please note that Threema Web is currently only available for Android. Support for other platforms is in preparation.
- On your desktop computer, open web.threema.ch (with Chromium, Google Chrome, Mozilla Firefox, or Opera)
- In the Threema app, select “Threema Web” and activate the scanner:
Android: Side drawer > Threema Web > plus sign
iOS/Windows Phone: Not yet available
- Use your mobile device to scan the QR code displayed on web.threema.ch
Hint: To avoid having to scan the QR code each time you use Threema Web, you can set a session password in the browser before scanning.
Threema Web is currently only available for the Android version of Threema. Threema for iOS and Threema for Windows Phone are not yet supported.
Since Threema Web is based on WebRTC data channels, Safari and Microsoft Edge are currently not supported.
You can also host Threema Web on your own server.
Threema Web currently provides the following features:
To use Threema Web without having to scan the QR code each time, you can set a session password.
On web.threema.ch, enter a session password before scanning the displayed QR code. To use Threema Web the next time on the same computer, you can simply enter this password (instead of scanning the QR code again).
This way, it’s also possible to use Threema if your mobile device isn’t present (provided it’s connected to the Internet).
The different sessions are listed in the Threema app, where you can remove and rename them.
These are Threema Web’s main characteristics and advantages:
- Threema Web allows to use Threema on the desktop without compromising security
- Threema Web reduces the digital footprint to the bare minimum by establishing a direct connection between desktop and mobile device
- No mirroring of the user’s message database – neither on a server nor on the desktop
- Since Threema Web is web-based, it is platform-independent
- Threema Web is open source
- Threema Web uses WebRTC, a tried and tested open standard for direct communication between two devices
- SaltyRTC ensures a secure connection between browser and mobile device
Threema Web establishes an encrypted direct connection between web browser and mobile device. This allows to synchronize messages directly between browser and mobile device, without having to temporarily store the messages on a server. In contrast to common, server-based approaches, the digital footprint is reduced to the bare minimum.
Once the session has ended, all synchronized messages are deleted in the browser. Threema Web acts merely as extension of the mobile app and hence meets Threema’s high security standard.
The technical details of Threema Web’s architecture are documented here.
If establishing a connection to Threema Web freezes at 60%, it’s not possible to connect browser and mobile device using WebRTC.
Please make sure you are using the latest version of a compatible browser.
Verify that no browser plugin (such as an ad blocker) is disabling WebRTC, and reload Threema Web.
If you are behind a (corporate) firewall or are using a VPN, Deep Packet Inspection might block WebRTC.
If, despite of using a session password, sessions are not being saved, browser settings might prevent the data necessary for restoring sessions of being stored locally.
Please adjust your browser settings as follows:
- Enter “chrome://settings/content” in the URL bar, and press Enter
- Click on “Manage exceptions…”
- Add “web.threema.ch” as hostname pattern, and set “Allow” as behavior
- Enter “about:preferences#privacy” in the URL bar, and press Enter
- If, in the “History” section, “Never remember history” is set, change this setting to “Use custom settings for history”
- Click the “Exceptions” button next to “Accept cookies from sites”
- As “Address of website”, enter “https://web.threema.ch/”, and click “Allow” and then “Save Changes”
- If (in the “History” section) “Clear history when Firefox closes” is activated, click the “Settings” button; if “Cookies” is checked, uncheck it and confirm by clicking “OK”
- Restart Firefox.
In order for Threema Web to display desktop notifications, the respective permission must be granted in the browser. If this permission was denied initially, it can be granted later as follows:
- Close Threema Web
- Insert “chrome://settings/content” in the URL bar, and press Enter
- Under “Notifications”, click “Manage exceptions”
- Change the Behavior of “https://web.threema.ch/” from “Block” to “Allow”
- Open Threema Web
- Close Threema Web
- Insert “about:preferences#content” in the URL bar, and press Enter
- Under “Notifications”, click “Choose…”
- First, select “https://web.threema.ch/”; then, click “Remove Site“ and “Save Changes”
- Open Threema Web, and grant permission to send notifications
- Close Threema Web
- Insert “opera://settings” in the URL bar, and press Enter
- First, click on “Websites”; then, under “Notifications”, click “Manage exceptions…”
- Change the Behavior of “https://web.threema.ch/” from “Block” to “Allow”
- Open Threema Web
Yes. However, there are a few limitations due to the characteristics of the Android emulation and the lack of Google Play Services.
- Polling is used for notifications.
- Location sharing is disabled. Received locations are displayed as a picture.
- Video compression is deactivated.
If you purchase Threema from the Amazon App Shop and later uninstall the Store app, it is not possible to update a previously installed app. Update Threema as follows:
- Create a complete backup.
- Install the newest Threema version from the Amazon App Shop.
Plugins: Please install the QR Code plugin and the Voice Message plugin directly from the Threema app, not from the Amazon App Store or the Threema Shop. Open the side drawer, select “Plugins”, and tap the download icon next to the plugin you would like to install. The plugin will be downloaded to your device’s “downloads” directory; install it using BlackBerry’s package installer.
Threema supports the following URL actions:
Adding an ID to the contact list
Adds the given ID to the contact list if it's not already on it, and shows the contact details.
Composing a message
For all URLs below, a parameter “id” can optionally be added to specify the target ID. If the ID is not supplied, a contact picker will be shown first. In all cases, user confirmation (pressing the “Send” button) will be required before the message/image is actually sent.
Opens a message composer and puts the given text in the input box.
threema://compose?image=pasteboard (only on iOS)
Accepts an (unencrypted) image on the general pasteboard. A message composer is opened and a preview of the image appears. The user can then send the image by tapping the appropriate button.
threema://compose?image=pasteboard&key=0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef (only on iOS)
Allows passing encrypted image data through the general pasteboard. The image data must be encrypted with AES256 in CBC mode with PKCS7 padding and a zero IV. A new, random key should be used for each invocation.The key must be given in hex. The pasteboard type (UTI) must be “ch.threema.app.imgenc”. If the image data has been successfully decrypted, a message composer is opened and a preview of the image appears. The user can then send the image by tapping the appropriate button.
File URL handling (only on iOS)
Threema accepts the UTI “public.image”. If an image file is opened with Threema (via UIDocumentInteractionController), a contact picker is shown. Once the user has chosen a contact, the message composer is opened and a preview of the image appears. The user can then send the image by tapping the appropriate button.
Android/iOS: To verify your phone number, simply tap the link in the message you have received.
Please note: If you have already entered the code manually, there’s no need to tap the link since your phone number has already been verified.
Windows Phone: In Threema, navigate to the “me” tab, tap the hourglass icon next to your phone number, and enter the code you have received.
Lost passphrases, PIN codes, and lock codes cannot be recovered. However, you can reset the app, and then set it up again. Please note: Unless you have a backup, you will lose all saved messages and your Threema ID.
Android: Delete the app data in Settings > Apps > Threema > Clear data.
iOS: Enter a wrong code ten times. A button will appear in the upper left-hand corner that allows you to reset the app data.
Windows Phone: Delete Threema, and reinstall it. All app data will be removed.
Threema Gateway is a communication solution for businesses. It enables customers to integrate Threema messages into their own software applications, both for sending and receiving text messages and files of up to 50 MB. Applications include:
- mTAN, OTP (One-time passwords)
- Alerting for emergency services, IT and technical installations
- Secure password exchange
- Forwarding of encrypted emails
- Secure news channel for companies' internal communication
- Confidential customer communications
Find out more about this product on gateway.threema.ch.
The management of chats and media files depends on your operating system:
In the side menu, navigate to Settings > Media & Storage > Storage Management, where you can check the storage and choose between the following options:
- Delete media and files which are older than the specified amount of time (1 week to 1 year)
- Delete messages which are older than the specified amount of time (1 week to 1 year)
Please note: Messages and media files are only deleted once you tap the button Delete Data or Delete Messages, respectively.
Selectively delete media files of specific chats: In a chat, select “Media Gallery” in the menu and use the drop-down menu to filter the listed files (all, images, videos, voice messages, other files). Tap and hold an item, and then tap on other items to add them to the selection (or tap the “Select all” button in the title bar to select all items). Finally, tap the trash-bin icon to delete the selected items.
Media files can be managed via the chat view: Open a chat, tap the title bar, and then tap on “Media” in the bar that appeared below the title bar. Select a file, and delete it by tapping the trash-bin icon in the full-screen view.
Navigate to Settings > Media + Storage, where you can check the storage and choose between the following options:
- Set the size of outgoing images. Using smaller sizes will reduce the volume of data transfer.
- Delete all video files
- Delete all image files
- Delete all voice messages
Ensuring security and privacy is our biggest mission. Therefore, the source code of both the server and the client software is externally reviewed on a regular basis.
Some of Threema’s core components are open source:
If some of your friends don’t use Threema yet, you can invite them as follows:
- Android: Navigate to the contact list, and scroll to the bottom. As a last contact, there will appear «Invite a Friend», where you can choose between email, text message and Twitter.
- iOS: In Threema, navigate to «Settings > Invite a Friend», and choose between email, text message, and Twitter.
- Windows Phone: You can share the following link, which leads to our website: https://three.ma