Slack's Pro plan costs $7.25 per user per month, and the free tier caps your searchable message history at 90 days. For a 20-person team, Slack Pro runs $1,740 per year. Rocket.Chat is a direct alternative: open-source team messaging you install on your own server, where the message archive is unlimited and the per-user cost on the community edition is zero. The project lives at github.com/RocketChat/Rocket.Chat with 45,890 GitHub stars.
| Fact | Value |
|---|---|
| What it is | Self-hosted team messaging and collaboration platform |
| Built by | Rocket.Chat Technologies Corp. (open-source community edition) |
| License | MIT (Community) |
| Platforms | Linux, Docker, cloud VPS; clients for iOS, Android, desktop, web |
| Requires | A server with at least 2 GB RAM; MongoDB database |
| Install method | Docker Compose or Linux snap package |
| Verdict | Install for team communication you fully control; evaluate if Slack's free tier already meets your team's needs |
What Rocket.Chat actually is
Rocket.Chat is an open-source team communication platform that covers the same ground as Slack: channels, direct messages, file sharing, threads, search, and integrations. The difference is ownership. When you run it on your own server, the message data lives in your database, subject to your retention policy, not a vendor's.
The community edition is licensed under the MIT license, a permissive open-source license that lets you run, modify, and distribute the software without restriction. That matters for organizations in regulated industries where the data residency terms of a commercial SaaS product create friction, or for teams building internal tooling who want to avoid a vendor dependency.
The platform requires MongoDB as its database. MongoDB is a database system that stores data in a flexible, document-based format rather than structured tables. You do not need to understand MongoDB to run Rocket.Chat; the Docker Compose setup handles it automatically.
At 45,890 GitHub stars, Rocket.Chat is one of the most widely deployed open-source communication tools in production, with mobile, desktop, and web clients all maintained alongside the server.
What you get after installing it
Messaging core: Channels are public or private, threads let you fork any message into a focused side conversation, and every message is fully indexed and searchable with no history cutoff on self-hosted deployments. Direct messages, group messages, emoji reactions, read receipts (an indicator showing when other participants have seen your message), and message translation are all included.
Voice, video, and calls: Audio and video calls use Jitsi by default (Jitsi is a free, open-source video conferencing system). WebRTC (a browser standard for sending audio and video directly between two users without routing through a central server) is also available for peer-to-peer calls. Screen sharing works alongside video.
Webhooks and the marketplace: An app marketplace covers Jira, GitHub, GitLab, Trello, Google Drive, and others. For anything outside the marketplace, incoming webhooks let external tools post messages to a channel. A webhook is a way for one tool to send an automatic notification to another when something happens; a monitoring system or CI/CD pipeline (the automated system that builds and deploys your code when changes are committed) can push alerts directly to a team channel by calling a URL you create in settings.
Federation and SSO: Federation lets multiple independently run Rocket.Chat servers communicate with each other, similar to how email works across providers: a user on your server can message a user on a partner organization's separate server. SSO, which stands for Single Sign-On, lets users authenticate with existing credentials from Google Workspace or an enterprise directory. Rocket.Chat supports LDAP (a directory protocol common in enterprise environments), OAuth (the standard used by Google and GitHub), and SAML (used by identity providers like Okta and Azure AD).
AI agent integration: Rocket.Chat supports incoming webhooks and a native AI Agent framework, so AI agents can post alerts, summaries, and results directly to team channels without a separate notification layer.
The install experience
The two practical paths are Docker Compose and the Linux snap package (snap is a packaging system built into Ubuntu that installs applications with all their dependencies bundled, similar to how a phone app store works).
Docker is software that packages an application into a container so it runs identically on any server. Docker Compose coordinates multiple containers together: Rocket.Chat, its MongoDB database, and a reverse proxy (a layer that forwards requests from the internet to the right internal service) all run as a unit. You pull the official compose file, set your environment variables, and start the stack with docker compose up -d. Then you configure a reverse proxy such as Nginx or Caddy and issue an SSL certificate via Let's Encrypt (a free service that provides the HTTPS certificates encrypting traffic between your server and users' browsers). Most people complete this in under an hour on a server they already know.
The snap package is simpler if you are on Ubuntu: one command installs the full bundle including MongoDB, and updates come automatically through the snap channel. The trade-off is less control over the MongoDB configuration.
Server requirements: the minimum is 2 GB RAM; a team of 10 to 20 users needs 4 GB for comfortable performance. That maps to a $6 to $12 per month VPS (a rented slice of a remote machine) from Hetzner, DigitalOcean, or Vultr.
If you have deployed a web app on a VPS before, neither path is hard. If this is your first server deployment, plan for a few hours of reading and working through DNS (Domain Name System, the system that maps your domain name to your server's IP address) configuration. The Rocket.Chat docs cover the common failure points.
Where it fits and what to compare it to
Slack (slack.com) is the default comparison. The UX is polished, the integrations library is larger, and onboarding is faster than any self-hosted alternative. For a team whose message history fits in the 90-day free tier and that has no interest in running infrastructure, Slack is the lower-friction choice. The trade-off is per-seat pricing that compounds as headcount grows and conversation data that lives on Slack's servers.
Mattermost is the other major open-source team chat alternative. It has stronger compliance features, better audit logging, and more granular access controls, which makes it the preferred choice in healthcare, financial services, and government environments. The interface is more austere. If your primary driver is regulatory compliance rather than feature breadth, Mattermost is worth evaluating alongside Rocket.Chat.
Microsoft Teams is bundled with Microsoft 365. For organizations already running Microsoft 365, Teams is the default because the cost is baked in and the SharePoint, OneDrive, and Outlook integration is tight. No self-hosting option exists.
Discord is free and fast, but it is consumer-focused and lacks SSO, LDAP integration, and the compliance controls that workplace deployments require.
Rocket.Chat is the right fit for a team that wants persistent, searchable history without per-seat billing, or that needs federation, custom SSO, or the built-in omnichannel inbox. For a solo operator or small team whose needs the free tier covers, Slack is the simpler starting point.
Verdict
Install for teams that have outgrown the 90-day Slack free tier or have a specific reason to keep message data off a third-party platform.
The cost argument is blunt. A 20-person team on Slack Pro pays $1,740 per year. The same team on Rocket.Chat Community Edition on a $10 per month VPS pays $120 per year, with a complete, unlimited message archive. The features that matter for daily communication including channels, threads, search, video calls, file sharing, and integrations are all present.
The MIT license is worth noting separately. You can run it commercially, embed it in a product, and modify the codebase without publishing your changes. That is different from tools with copyleft licenses (open-source licenses that require you to publish any modifications) and different from proprietary SaaS where access depends on a continuing vendor relationship.
The caveats: you are responsible for server upkeep, MongoDB maintenance, and version updates. There is no managed update path for self-hosted deployments. The initial install requires comfort with Docker or Linux server administration. For a team watching Slack's per-seat bill compound, or an organization where data residency is a hard requirement, Rocket.Chat is a capable, actively maintained alternative backed by 45,890 GitHub stars and active commits through 2026.