European Alternative to Mattermost

Element

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by Element

Element is a secure messenger and collaboration platform built on the Matrix open protocol, developed by Element (formerly New Vector) in London, UK. It provides end-to-end encrypted messaging, voice/video calls, and bridging to other platforms (Slack, Teams, WhatsApp). Element is used by the French government, German military (Bundeswehr), and NATO for secure communications. Organizations can self-host for complete data sovereignty, or use Element's managed hosting.

Wire

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by Wire

Wire is a secure collaboration platform founded in 2012 by Janus Friis (Skype co-founder) and headquartered in Zug, Switzerland. It offers end-to-end encrypted messaging, voice/video calls, and file sharing for teams. Wire is open source, independently audited, and used by government agencies and enterprises across Europe for classified communications. It supports self-hosted deployment for organizations requiring full data sovereignty.

Threema

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by Threema

Threema is a Swiss encrypted messenger founded in 2012 by Manuel Kasper in Pfäffikon, Switzerland. Unlike most messaging apps, Threema requires no phone number or email to register — users get a random Threema ID, enabling truly anonymous communication. All messages, calls, and files are end-to-end encrypted, and metadata is minimized by design. Threema is fully open source and has been independently audited. It's widely adopted in German-speaking countries and used by the Swiss government and military.

Stoat

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by Stoat

Stoat (formerly Revolt, rebranded in October 2025) is an open-source, privacy-focused messaging platform built in the UK. It provides a familiar Discord-like experience with servers, channels, voice chat, and rich media sharing — but with full GDPR compliance and EU data hosting. Stoat is fully self-hostable, giving communities and teams complete control over their data. It features fine-grained role-based permissions, end-to-end encryption, and does not require a phone number or real name to register. Ideal for privacy-conscious communities looking for a feature-rich alternative to Discord.