Threema OnPrem is a self-hosted, enterprise-grade messaging solution developed for organizations that demand maximum privacy, full data control, and unmatched security. Designed with sensitive sectors in mind—such as government bodies, law enforcement, and industrial enterprises—Threema OnPrem combines Threema’s proven security architecture with complete system autonomy.
Unlike cloud-based messengers, Threema OnPrem runs entirely within your organization’s infrastructure, making it the ideal platform for secure internal communication even in crisis situations or when public networks are down.
Ultimate Security & Full Data Ownership
· No external servers involved—communication remains fully internal
· No third-party access to messages, media, or metadata
· End-to-end encryption for all data, including messages, voice/video calls, and files
· Private chats protected by PIN or fingerprint
· No phone number or email required for use
Flexible Administration & Integration
· Central admin portal with:
o User and permission management
o Security configurations
o Usage statistics
o Mobile Device Management (MDM) and BYOD support
· Integrates easily into existing IT security environments
· Operates independently of public networks—ideal for disaster recovery
Full-Featured Secure Chat App
· One-on-one and group chats with emoji reactions
· Text formatting (bold, italic, ~strikethrough~)
· Polls for fast decision-making within teams
· Send text, voice messages, files, media, and locations
· Edit or delete messages for everyone after sending
· Anonymous communication—no address book or SIM needed
· Optional contact syncing and QR code verification for secure connections
Voice & Video Communication
· Crystal-clear voice and video calls, fully encrypted
· Group audio/video calls with one-tap join
· No need to expose personal phone numbers
Cross-Platform Availability
· Use Threema on mobile devices, desktops, and tablets
· Full chat history and media access across devices
· Light and dark themes for a personalized experience
Note
To use Threema OnPrem, the system must be installed and configured on your organization’s own servers. This solution is not available for private users.
Learn more: https://threema.ch/onprem
FAQs
1. What Android permissions does Threema OnPrem use and why?
Threema requires several permissions for functionality:
· Contacts: Needed only if contact sync is enabled.
· Camera: For QR code verification and in-app camera usage.
· Microphone: Used for voice messages and calls.
· Location: Supports the “send location” feature.
· Accounts: Assists with contact sync and account management.
· Storage: For saving and accessing shared files and media.
· Phone calls: Allows the app to mute incoming calls during Threema calls.
2. Is Threema OnPrem available to individual users?
No. Threema OnPrem is designed for organizational use and must be hosted on a company’s own servers. It is not intended for private users.
3. Can Threema OnPrem function during internet outages?
Yes. It can operate independently of public internet networks, making it perfect for crisis management and ensuring uninterrupted internal communication.
4. Is it possible to make video calls without sharing my phone number?
Yes. Threema supports fully encrypted voice and video calls without requiring users to share personal numbers, ensuring full anonymity.
5. How are group chats managed securely?
Group chats use a decentralized structure—only the group members are aware of the group's composition. Not even Threema has access to group details.
Version History
v5.6.1o—26 Nov, 2024
- Refactoring of notification channels: Individual notification settings need to be set again
- Media can now be edited before forwarding
- The edit history can now be viewed for edited messages
- The job title and department can now be displayed for company contacts
v5.8.2o—10 Apr, 2025
- Emoji reactions are now included in the data backup
- Fixed a bug that caused custom ringtones to be reset when starting the app
v5.8.1o—27 Feb, 2025
- New: You can now react to messages with emoji
- Fixed a bug concerning profile pictures in group calls
