head to head · open source
Rocket.Chat vs cobalt
Rocket.Chat has 46,133 GitHub stars, 13,891 forks, 4,023 open issues and last shipped yesterday. cobalt has 43,316 stars, 3,798 forks, 269 open issues and last shipped 6 months ago. Rocket.Chat leads on adoption by 7% (46,133 vs 43,316 stars). Rocket.Chat is written in TypeScript under a custom or non-standard licence; cobalt is written in Svelte under AGPL-3.0. Rocket.Chat has attracted 30% as many forks as stars, cobalt 9%. Rocket.Chat was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 2 topic tags (collaboration, javascript), so they are genuine substitutes rather than adjacent tools.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| Rocket.Chat | cobalt | |
|---|---|---|
| GitHub stars | ★ 46K | ★ 43K |
| License | Custom / other | AGPL-3.0 |
| Written in | TypeScript | Svelte |
| Last push | 2026-09-17 | 2026-04-06 |
| Forks | ⑂ 14K | ⑂ 3.8K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Rocket.Chat if
- You weight community size — 46K stars and counting
- You want the Custom / other license terms
- Your stack matches TypeScript
- You value the larger contributor base for long-term maintenance
pick cobalt if
- You want the cobalt feature set and don't need the biggest community
- You prefer the AGPL-3.0 license terms
- Your stack matches Svelte
- You evaluated both and cobalt fits your workflow better
About Rocket.Chat
Rocket.Chat is an open source, self hostable team communications platform written in TypeScript that gives organisations full ownership of their messaging, voice, and federation infrastructure instead of renting it from a closed SaaS vendor.
read the full Rocket.Chat overview →
About cobalt
cobalt is a media downloader built around a single promise: paste a link, get the file, move on. It is a monorepo containing the source for an API, a web frontend, and related packages, written primarily in Svelte and TypeScript. The project lives in the modern web and JavaScript ecosystem, and its public surface is hosted at cobalt.tools, while the full codebase is published under the AGPL 3.0 license.
read the full cobalt overview →
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Frequently asked questions
Is Rocket.Chat or cobalt more popular?
Rocket.Chat has 46,133 GitHub stars and cobalt has 43,316. Rocket.Chat has the larger community by that measure.
Are Rocket.Chat and cobalt free?
Both are open source. Rocket.Chat has no licence declared in this registry, and cobalt is licensed under AGPL-3.0. Both are free to self-host.
What is the difference between Rocket.Chat and cobalt?
Rocket.Chat is written in TypeScript and cobalt in Svelte. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, Rocket.Chat or cobalt?
Choose Rocket.Chat if you want the larger community (46,133 stars) or its Custom / other licence terms. Choose cobalt if its feature set, stack or AGPL-3.0 licence fits better. Both are self-hostable.