head to head · open source
excelize vs Billion Mail
excelize has 20,918 GitHub stars, 1,949 forks, 131 open issues and last shipped 2 days ago. Billion Mail has 15,611 stars, 1,702 forks, 236 open issues and last shipped 3 months ago. excelize leads on adoption by 34% (20,918 vs 15,611 stars). excelize is written in Go under BSD-3-Clause; Billion Mail is written in Go under AGPL-3.0. excelize has attracted 9% as many forks as stars, Billion Mail 11%. excelize 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
| excelize | Billion Mail | |
|---|---|---|
| GitHub stars | ★ 21K | ★ 16K |
| License | BSD-3-Clause | AGPL-3.0 |
| Written in | Go | Go |
| Last push | 2026-09-16 | 2026-06-11 |
| Forks | ⑂ 1.9K | ⑂ 1.7K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick excelize if
- You weight community size — 21K stars and counting
- You want the BSD-3-Clause license terms
- Your stack matches Go
- You value the larger contributor base for long-term maintenance
pick Billion Mail if
- You want the Billion Mail feature set and don't need the biggest community
- You prefer the AGPL-3.0 license terms
- Your stack matches Go
- You evaluated both and Billion Mail fits your workflow better
About excelize
Excelize is a pure Go library for reading and writing XLAM, XLSM, XLSX, XLTM and XLTX spreadsheets, built for Go developers who need to generate or parse Microsoft Excel 2007 and later workbooks directly from their own code.
read the full excelize overview →
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 →
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Frequently asked questions
Is excelize or Billion Mail more popular?
excelize has 20,918 GitHub stars and Billion Mail has 15,611. excelize has the larger community by that measure.
Are excelize and Billion Mail free?
Both are open source. excelize is licensed under BSD-3-Clause and Billion Mail under AGPL-3.0. Neither carries a licence fee.
What is the difference between excelize and Billion Mail?
excelize is written in Go and Billion Mail in Go. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, excelize or Billion Mail?
Choose excelize if you want the larger community (20,918 stars) or its BSD-3-Clause licence terms. Choose Billion Mail if its feature set, stack or AGPL-3.0 licence fits better. Both are self-hostable.