Element: Open Source Alternative to Slack and Rocket.Chat

Element is an open-source collaboration client built on Matrix, an open, decentralized communication protocol. Unlike Rocket.Chat, which runs as a single self-hosted server, Matrix federates across many independent servers, so users on different homeservers can message each other — closer to how email works than to a single-vendor platform.

What is Element?

Element provides end-to-end encrypted messaging, voice, and video on top of Matrix. Because it's protocol-based, it interoperates with other Matrix clients (like Cinny), and organizations can run their own homeserver for full data sovereignty. It's AGPL-3.0 licensed.

Element vs Rocket.Chat

Feature	Element	Rocket.Chat
License	AGPL-3.0	MIT
Architecture	Federated (Matrix protocol)	Single self-hosted server
Encryption	End-to-end by default	Optional E2E
Interoperability	Any Matrix client/server	Rocket.Chat ecosystem

Choose Element if federation, cross-server interoperability, or default end-to-end encryption matters. Choose Rocket.Chat if you prefer a single, all-in-one self-hosted server without protocol complexity.

At a glance

Attribute	Details
License	AGPL-3.0
Category	Collaboration
Stack	TypeScript (Matrix protocol)
Self-hosted	Yes — via a Matrix homeserver
Alternatives	Slack, Rocket.Chat, Discord, Microsoft Teams

FAQ

Is Element a free, open-source alternative to Slack?

Yes. Element is AGPL-3.0 licensed and free to self-host, though running Matrix requires operating a homeserver (e.g. Synapse or Dendrite).

What's the difference between Element and Rocket.Chat?

Element is built on the federated Matrix protocol, so different servers can interoperate and messages are end-to-end encrypted by default. Rocket.Chat is a single self-hosted server with optional encryption.

What are the top open-source alternatives to Slack?

Browse more open-source alternatives to Slack, or explore the full Collaboration category.