head to head · open source
Mastodon vs pump.io
Mastodon has 50,299 GitHub stars, 7,498 forks, 4,525 open issues and last shipped yesterday. pump.io has 2,238 stars, 328 forks, 679 open issues and last shipped 7 months ago. Mastodon leads on adoption by 2,147% (50,299 vs 2,238 stars). Mastodon is written in Ruby under AGPL-3.0; pump.io is written in JavaScript under Apache-2.0. Mastodon has attracted 15% as many forks as stars, pump.io 15%. Mastodon was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (social-network), 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
| Mastodon | pump.io | |
|---|---|---|
| GitHub stars | ★ 50K | ★ 2.2K |
| License | AGPL-3.0 | Apache-2.0 |
| Written in | Ruby | JavaScript |
| Last push | 2026-09-17 | 2026-02-12 |
| Forks | ⑂ 7.5K | ⑂ 328 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Mastodon if
- You weight community size — 50K stars and counting
- You want the AGPL-3.0 license terms
- Your stack matches Ruby
- You value the larger contributor base for long-term maintenance
pick pump.io if
- You want the pump.io feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches JavaScript
- You evaluated both and pump.io fits your workflow better
About Mastodon
Mastodon is a free, open source, self hosted social network server built on ActivityPub that lets anyone run a microblogging community which interoperates with the wider Fediverse, and it is aimed at individuals, communities, and organisations that want to own their social graph instead of renting it from a platform.
read the full Mastodon overview →
About pump.io
pump.io is a social server and stream server written in JavaScript for Node.js, and it lives in the open source ActivityStreams and social networking ecosystem. The project provides an ActivityStreams API, uses activitystrea.ms JSON as the main data and command format, and includes a web interface. Its documented purpose is to let a person post something and have followers see it, while also exposing social data in a machine readable form.
read the full pump.io overview →
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Frequently asked questions
Is Mastodon or pump.io more popular?
Mastodon has 50,299 GitHub stars and pump.io has 2,238. Mastodon has the larger community by that measure.
Are Mastodon and pump.io free?
Both are open source. Mastodon is licensed under AGPL-3.0 and pump.io under Apache-2.0. Neither carries a licence fee.
What is the difference between Mastodon and pump.io?
Mastodon is written in Ruby and pump.io in JavaScript. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, Mastodon or pump.io?
Choose Mastodon if you want the larger community (50,299 stars) or its AGPL-3.0 licence terms. Choose pump.io if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.