head to head · open source
Inbox Zero vs Sessy
Inbox Zero has 12,895 GitHub stars, 1,653 forks, 209 open issues and last shipped yesterday. Sessy has 944 stars, 44 forks, 7 open issues and last shipped 4 days ago. Inbox Zero leads on adoption by 1,266% (12,895 vs 944 stars). Inbox Zero is written in TypeScript under a custom or non-standard licence; Sessy is written in Ruby under a custom or non-standard licence. Inbox Zero has attracted 13% as many forks as stars, Sessy 5%. Inbox Zero was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (email), 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
| Inbox Zero | Sessy | |
|---|---|---|
| GitHub stars | ★ 13K | ★ 944 |
| License | Custom / other | Custom / other |
| Written in | TypeScript | Ruby |
| Last push | 2026-11-02 | 2026-10-30 |
| Forks | ⑂ 1.7K | ⑂ 44 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Inbox Zero if
- You weight community size — 13K 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 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 Inbox Zero
Inbox Zero your 24/7 AI email assistant Organizes your inbox, pre drafts replies, manages your calendar, and organizes attachments. Chat with it from Slack or Telegram to manage your inbox on the go. Open source alternative to Fyxer, but more customizable and secure. Website · Discord · Issues Mission To help you spend less time in your inbox, so you can focus on what matters most. Features AI Personal Assistant: Organizes your inbox and pre drafts replies in your tone and style. AI Rules for email: Explain in plain English how your AI should handle your inbox. Reply Zero: Track emails to reply to and those…
read the full Inbox Zero overview →
About Sessy
Sessy Open source email observability for AWS SES by Marc Köhlbrugge. What is Sessy? Amazon SES is a fantastic email service: cost effective, reliable, and great deliverability. But it's frustratingly difficult to see what's actually happening with your emails. That's why many people turn to overpriced email services that are often just glorified SES wrappers with a nice UI. You end up paying a lot for something you could do yourself. Sessy is the open source alternative. Use raw SES and still get a beautiful interface to see what happens after you hit send: deliveries, bounces, complaints, opens, clicks, and…
read the full Sessy overview →
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Frequently asked questions
Is Inbox Zero or Sessy more popular?
Inbox Zero has 12,895 GitHub stars and Sessy has 944. Inbox Zero has the larger community by that measure.
Are Inbox Zero and Sessy free?
Neither Inbox Zero nor Sessy declares a licence in this registry, so check each project's own repository before relying on either for a commercial use. Both are free to self-host.
What is the difference between Inbox Zero and Sessy?
Inbox Zero 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, Inbox Zero or Sessy?
Choose Inbox Zero if you want the larger community (12,895 stars) or its Custom / other licence terms. Choose Sessy if its feature set, stack or Custom / other licence fits better. Both are self-hostable.