When using a messaging service, the question who else is on that platform inevitably arises. In conventional chat apps, the contact list answers this question conclusively. In Threema, where privacy is a top priority and users are not forced to disclose their phone number, the contact list might not reveal every contact who uses the service.
Messengers like WhatsApp or Signal use the phone number as unique identifier. Since the phone number is personal data that points to the identity of its owner, Threema uses a random string of characters (the “Threema ID”) instead, and providing a phone number is optional.
Only contacts who have linked a phone number to their Threema ID appear automatically in Threema’s contact list.
There are different reasons to not disclose one’s phone number and use Threema anonymously. Out of all users, about 30% use Threema this way. Therefore, it’s likely that also some of your contacts don’t show up in your contact list.
How to Get Even More Contacts on Board
Send your individual Share Link to friends who don’t appear in your contact list, and add this link to your email signature, for example. Those who don’t use Threema yet can download it using this link and contact you as soon as they have done so.
If you still use other chat services you intend to leave due to privacy concerns, consider setting this image as profile picture to let others know where to contact you in the future: