head to head · open source
Billion Mail vs preswald
Billion Mail has 15,619 GitHub stars, 1,704 forks, 236 open issues and last shipped 3 months ago. preswald has 4,269 stars, 646 forks, 330 open issues and last shipped 3 months ago. Billion Mail leads on adoption by 266% (15,619 vs 4,269 stars). Billion Mail is written in Go under AGPL-3.0; preswald is written in Python under Apache-2.0. Billion Mail has attracted 11% as many forks as stars, preswald 15%. preswald 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
| Billion Mail | preswald | |
|---|---|---|
| GitHub stars | ★ 16K | ★ 4.3K |
| License | AGPL-3.0 | Apache-2.0 |
| Written in | Go | Python |
| Last push | 2026-06-11 | 2026-06-11 |
| Forks | ⑂ 1.7K | ⑂ 646 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Billion Mail if
- You weight community size — 16K stars and counting
- You want the AGPL-3.0 license terms
- Your stack matches Go
- You value the larger contributor base for long-term maintenance
pick preswald if
- You want the preswald feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Python
- You evaluated both and preswald fits your workflow better
About Billion Mail
BillionMail is an open source mail server and email marketing platform written in Go and released under the AGPL 3.0 license. It lives in the self hosted email ecosystem and is described as a solution for newsletters, promotional emails, and transactional messages. The project combines mail server topics such as Postfix, Dovecot, Rspamd, and SMTP with campaign features such as customer management, analytics, templates, and sending control.
read the full Billion Mail overview →
About preswald
Preswald is an Apache 2.0 Python static site generator that packages interactive data apps — compute, data access, and UI — into self contained .html files that run entirely in the browser on a WebAssembly runtime built from Pyodide and DuckDB, aimed at analysts, data engineers, and developers who need to hand a working dashboard, report, or inspection tool to someone who will not install anything.
read the full preswald overview →
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Frequently asked questions
Is Billion Mail or preswald more popular?
Billion Mail has 15,619 GitHub stars and preswald has 4,269. Billion Mail has the larger community by that measure.
Are Billion Mail and preswald free?
Both are open source. Billion Mail is licensed under AGPL-3.0 and preswald under Apache-2.0. Neither carries a licence fee.
What is the difference between Billion Mail and preswald?
Billion Mail is written in Go and preswald in Python. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, Billion Mail or preswald?
Choose Billion Mail if you want the larger community (15,619 stars) or its AGPL-3.0 licence terms. Choose preswald if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.