head to head · open source
Tongsuo vs pki
Tongsuo has 1,535 GitHub stars, 260 forks, 160 open issues and last shipped 13 days ago. pki has 509 stars, 162 forks, 46 open issues and last shipped 2 days ago. Tongsuo leads on adoption by 202% (1,535 vs 509 stars). Tongsuo is written in C under Apache-2.0; pki is written in Java under GPL-2.0. Tongsuo has attracted 17% as many forks as stars, pki 32%. pki was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (pki), 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
| Tongsuo | pki | |
|---|---|---|
| GitHub stars | ★ 1.5K | ★ 509 |
| License | Apache-2.0 | GPL-2.0 |
| Written in | C | Java |
| Last push | 2026-09-07 | 2026-09-18 |
| Forks | ⑂ 260 | ⑂ 162 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Tongsuo if
- You weight community size — 1.5K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches C
- You value the larger contributor base for long-term maintenance
pick pki if
- You want the pki feature set and don't need the biggest community
- You prefer the GPL-2.0 license terms
- Your stack matches Java
- You evaluated both and pki fits your workflow better
About Tongsuo
Tongsuo (铜锁) is an open source C library of modern cryptographic primitives and secure communication protocols, developed under the OpenAtom Foundation, and it is built for teams that need Chinese commercial cryptography, TLS, PKI, and privacy preserving primitives from a single dependency.
read the full Tongsuo overview →
About pki
Dogtag PKI is an enterprise class open source Certificate Authority suite, written in Java and licensed under GPL 2.0, for administrators who need to run their own certificate lifecycle infrastructure rather than buy it as a hosted service.
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Frequently asked questions
Is Tongsuo or pki more popular?
Tongsuo has 1,535 GitHub stars and pki has 509. Tongsuo has the larger community by that measure.
Are Tongsuo and pki free?
Both are open source. Tongsuo is licensed under Apache-2.0 and pki under GPL-2.0. Neither carries a licence fee.
What is the difference between Tongsuo and pki?
Tongsuo is written in C and pki in Java. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, Tongsuo or pki?
Choose Tongsuo if you want the larger community (1,535 stars) or its Apache-2.0 licence terms. Choose pki if its feature set, stack or GPL-2.0 licence fits better. Both are self-hostable.