Threema. The Secure Messenger

72.5K reviews
Content rating
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About this app

Threema is the world’s best-selling secure messenger and keeps your data out of the hands of hackers, corporations, and governments. The service can be used completely anonymously. Threema is open source and offers every feature one would expect from a state-of-the-art instant messenger. The app also allows you to make end-to-end encrypted voice, video, and group calls. Using the desktop app and the web client, you can also use Threema from your desktop.

Threema is designed from the ground up to generate as little data on servers as possible. Group memberships and contact lists are managed on your device only and never stored on our servers. Messages are immediately deleted after they have been delivered. Local files are stored encrypted on your mobile phone or tablet. All this effectively prevents the collection and misuse of your personal information, including metadata. Threema is fully compliant with the European privacy legislation (GDPR).

Threema end-to-end encrypts all your communication, including messages, voice and video calls, group chats, files, and even status messages. Only the intended recipient, and nobody else, can read your messages. Threema uses the trusted open source NaCl cryptography library for encryption. The encryption keys are generated and safely stored on the users’ devices to prevent backdoor access or copies.

Threema is not only an encrypted and private messenger but also versatile and feature-rich.

• Write text and send voice messages
• Make voice, video and group calls
• Share videos pictures and locations
• Send any type of file (pdf animated gif, mp3, doc, zip, etc.)
• Use the desktop app or the web client to chat from your computer
• Create groups
• Conduct polls with the poll feature
• Choose between a dark and a light theme
• Quickly and silently reply with the unique agree/disagree feature
• Verify the identity of a contact by scanning their personal QR code
• Use Threema as anonymous instant messaging tool
• Synchronize your contacts (optional)

All our servers are located in Switzerland, and we develop our software in-house.

Each Threema user receives a random Threema ID for identification. A phone number or email address is not required to use Threema. This unique feature allows you to use Threema completely anonymously – no need to give up private information or to open an account.

The source code of the Threema app is open for everyone to review. On top of that, renowned experts are regularly commissioned to conduct systematic security audits of Threema’s code.

Threema is not financed by advertising and does not collect user data.

For questions or problems please consult our FAQs:
Updated on
Mar 21, 2024

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
No data shared with third parties
Learn more about how developers declare sharing
No data collected
Learn more about how developers declare collection
Data is encrypted in transit
You can request that data be deleted

Ratings and reviews

69.8K reviews
Mikaela T
December 14, 2023
Sad update 12/12/23: the app keeps crashing now and i have to reinstall constantly and it lost all my info. 9/11/22: Like it but it's very glitchy. Messages sometimes take a while to send but I get the icons so I'm not guessing if it did or not. The video is hit or miss for instances will hang up on occasion. If you receive an incoming call or if you bluetooth disconnects. Love that it has a pin setting and not tie to phone number. Seems very dependable for keeping things secure.
388 people found this review helpful
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Threema GmbH
December 15, 2023
The cause of the crashes lies with the Android runtime system and unfortunately cannot be resolved by us. Several related tickets are currently pending with Google, e.g. We hope for a solution from Google soon and for your patience. For support with the other issues:
Lee Thompson
August 16, 2020
Consistently exceeds expectations! I have used Threema for years and, if they had stayed with the earliest versions of the app, I'd still purchase it! In addition to the encryption and security, they have continually added features that aren't seen elsewhere with the encryption and security Threema provides. If someone with whom I regularly communicate does not already have it, I purchase it for them. For everything Threema provides, especially at the price, it's ludicrous to not have it!
391 people found this review helpful
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Gene Blum
August 12, 2020
Can't recommend this enough. The only thing it's missing is self destructing messages, but that's not really as reliable as you might think. You should always be careful of the things you send no matter what and that you full trust the person on the other end. If you care about your security and still want group texts, then Theema is the absolute best messaging app for you. Not having to tie your phone number or email to your account is a huge plus for me, while for some people it's nice to be able to see all of your pre-existing contacts (which you can still totally do if you want) I prefer not to just have people be able to find me like that. I had some of my friends downloaded it (I even paid for some of them to get it, because it's that good) and walked them through skipping adding their phone number and email, had them add a master password (which you have to enter when you turn your phone on; optional) and PIN. You can set the PIN for individual chats. I have one group with 10 people who exchange books with each other. There are polls, now there's video chat to compliment the phone calls, you can transfer your account between phones, there's a web client, the servers are in Switzerland, end-to-end encryption by default, you can verify and add your contacts phones by scanning their QR code to avoid "man in the middle" attacks, and best of all you can just totally ditch your account; delete everything and start over whenever you want with a new anonymous ID. Seriously, I cannot stress it enough, if you genuinely care about security you need to buy this app and get your contacts to but it. Sure you can get Signal, which is tied to your phone number (not to mention gets part of its funding from the State Department and has a broken desktop app that stores everything in plain texts files) or WhatsApp (which is owned by Facebook and probably collects your data to sell you garbage) for free, but your paying for the real thing when you get Threema.
497 people found this review helpful
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What's new

- Added a highlighter pen function to image editor
- Support for animated WebP images
- Numerous optimizations and bug fixes