Threema

Threema is a Swiss secure instant messenger that provides end-to-end encrypted messaging, voice and video calls, and file sharing for private users and organizations. It addresses the need for confidential communication without requiring a phone number or email address, using a unique Threema ID for anonymous use. The platform is designed around a zero-knowledge architecture, meaning message content is accessible only to intended recipients, with minimal metadata retained on servers.

Core features include text and voice messages, groups and distribution lists, polls, file and location sharing, and end-to-end encrypted voice, video, and group calls. It runs on mobile devices, tablets, desktop apps, and a web client. Business editions add a management cockpit for centralized permission configuration, availability status, and screen sharing in group calls. Threema OnPrem supports self-hosted deployment with whitelabeling and DualLock remote access blocking. The platform integrates with Threema Broadcast for one-to-many messaging and Threema Gateway for external system connectivity. Open-source encryption technology and regular external security audits support its security model.

Threema serves individuals, businesses, public authorities, and security-critical organizations. It is offered as Threema Private for personal use, Threema Work for cloud-hosted business communication, and Threema OnPrem for self-hosted deployment. Threema Work is available with a free trial period, and business plans are organized into editions, including a Professional tier.