head to head · open source
Signal vs certificates
Signal has 29,364 GitHub stars, 6,892 forks, 498 open issues and last shipped 2 days ago. certificates has 8,885 stars, 597 forks, 299 open issues and last shipped 3 days ago. Signal leads on adoption by 230% (29,364 vs 8,885 stars). Signal is written in Kotlin under AGPL-3.0; certificates is written in Go under Apache-2.0. Signal has attracted 23% as many forks as stars, certificates 7%. Signal 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
| Signal | certificates | |
|---|---|---|
| GitHub stars | ★ 29K | ★ 8.9K |
| License | AGPL-3.0 | Apache-2.0 |
| Written in | Kotlin | Go |
| Last push | 2026-09-18 | 2026-09-17 |
| Forks | ⑂ 6.9K | ⑂ 597 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Signal if
- You weight community size — 29K stars and counting
- You want the AGPL-3.0 license terms
- Your stack matches Kotlin
- You value the larger contributor base for long-term maintenance
pick certificates if
- You want the certificates feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Go
- You evaluated both and certificates fits your workflow better
About Signal
Signal Android is a secure messaging application for Android devices that delivers private communication via end to end encryption. Developed by Signal Messenger, LLC, it operates within the broader Signal ecosystem, which includes official iOS and desktop clients. The app uses mobile data or Wi Fi to send and receive encrypted messages, voice calls, and video calls without relying on traditional SMS or telephony infrastructure.
read the full Signal overview →
About certificates
step ca is an open source online certificate authority that issues X.509 and SSH certificates and runs as an ACME server, built for DevOps teams that need automated certificate management without a commercial PKI contract.
read the full certificates overview →
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Frequently asked questions
Is Signal or certificates more popular?
Signal has 29,364 GitHub stars and certificates has 8,885. Signal has the larger community by that measure.
Are Signal and certificates free?
Both are open source. Signal is licensed under AGPL-3.0 and certificates under Apache-2.0. Neither carries a licence fee.
What is the difference between Signal and certificates?
Signal is written in Kotlin and certificates 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, Signal or certificates?
Choose Signal if you want the larger community (29,364 stars) or its AGPL-3.0 licence terms. Choose certificates if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.