head to head · open source
Plunk vs Sessy
Plunk has 5,474 GitHub stars, 401 forks, 61 open issues and last shipped 4 days ago. Sessy has 929 stars, 44 forks, 7 open issues and last shipped 3 days ago. Plunk leads on adoption by 489% (5,474 vs 929 stars). Plunk is written in TypeScript under AGPL-3.0; Sessy is written in Ruby under a custom or non-standard licence. Plunk has attracted 7% as many forks as stars, Sessy 5%. Sessy was the more recently maintained of the two, and both are self-hostable with no licence fee.
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
| Plunk | Sessy | |
|---|---|---|
| GitHub stars | ★ 5.5K | ★ 929 |
| License | AGPL-3.0 | Custom / other |
| Written in | TypeScript | Ruby |
| Last push | 2026-09-14 | 2026-09-15 |
| Forks | ⑂ 401 | ⑂ 44 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Plunk if
- You weight community size — 5.5K stars and counting
- You want the AGPL-3.0 license terms
- Your stack matches TypeScript
- You value the larger contributor base for long-term maintenance
pick Sessy if
- You want the Sessy feature set and don't need the biggest community
- You prefer the Custom / other license terms
- Your stack matches Ruby
- You evaluated both and Sessy fits your workflow better
About Plunk
Plunk is an open source email platform written in TypeScript and released under the AGPL 3.0 license. It combines transactional email, marketing campaigns, and workflow automation in a single system, and it is positioned as a self hosted alternative to SendGrid, Resend, and Mailgun. The project lives in the TypeScript and Node.js ecosystem, ships as a Docker image, and is documented at docs.useplunk.com with a community Discord for support.
read the full Plunk overview →
About Sessy
Sessy is an open source email observability tool for Amazon SES, built in Ruby on Rails by Marc Köhlbrugge and distributed under the O'Saasy License. It lives in the AWS ecosystem: you keep sending through raw SES, and Sessy supplies the interface that shows what happened to each message after it left your application. The repository carries the topics amazon ses, email, rails, and ruby, and the project's own homepage is sessy.do.
read the full Sessy overview →
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Frequently asked questions
Is Plunk or Sessy more popular?
Plunk has 5,474 GitHub stars and Sessy has 929. Plunk has the larger community by that measure.
Are Plunk and Sessy free?
Both are open source. Plunk is licensed under AGPL-3.0, and Sessy has no licence declared in this registry. Both are free to self-host.
What is the difference between Plunk and Sessy?
Plunk is written in TypeScript and Sessy in Ruby. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, Plunk or Sessy?
Choose Plunk if you want the larger community (5,474 stars) or its AGPL-3.0 licence terms. Choose Sessy if its feature set, stack or Custom / other licence fits better. Both are self-hostable.