Rocket.Chat

Rocket.Chat is an open source communication platform built for organizations that can't hand their data to a third-party cloud. It brings together real-time messaging, voice and video calls, screen sharing, and AI-assisted workflows into a single environment you host and control entirely.

Security is central to the design. It supports on-premises, air-gapped, and secure cloud deployments, and has been used on classified U.S. government networks including NIPRNet, SIPRNet, and JWICS. It holds DoD Authorization to Operate (ATO) up to Impact Level 6. It's also ISO 27001 certified and SOC 2 Type II compliant, and ships through the DoD's Iron Bank hardened container registry and the AWS Intelligence Community Marketplace. Few commercial team chat tools come close to that clearance level.

Beyond defense and intelligence, it fits any organization where data sovereignty matters: government agencies, critical infrastructure operators, financial institutions, and enterprises subject to strict regulatory requirements. The Swedish Electrical Safety Board and EU agency eu-LISA both use it for secure internal and cross-organizational collaboration.

Core capabilities include end-to-end encrypted conversations (enabled per room), granular access controls, fine-grained data retention policies, and comprehensive audit logs. Federated communication lets teams coordinate across organizational or jurisdictional boundaries without routing data through external services.

The architecture is extensible, MIT-licensed, and backed by more than 1,000 contributors. Teams can install pre-built apps or build custom integrations to fit specific workflows, without being locked into a vendor's roadmap. If you want something lighter, Mattermost is a comparable self-hosted option worth considering. The built-in AI features handle routine tasks and surface relevant information during active conversations — for teams that want a standalone AI layer instead, LLMChat takes a different approach.