head to head · open source
Signal vs certstrap
Signal has 29,359 GitHub stars, 6,890 forks, 498 open issues and last shipped yesterday. certstrap has 2,454 stars, 212 forks, 32 open issues and last shipped 8 months ago. Signal leads on adoption by 1,096% (29,359 vs 2,454 stars). Signal is written in Kotlin under AGPL-3.0; certstrap is written in Go under Apache-2.0. Signal has attracted 23% as many forks as stars, certstrap 9%. 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 | certstrap | |
|---|---|---|
| GitHub stars | ★ 29K | ★ 2.5K |
| License | AGPL-3.0 | Apache-2.0 |
| Written in | Kotlin | Go |
| Last push | 2026-09-18 | 2026-02-03 |
| Forks | ⑂ 6.9K | ⑂ 212 |
| 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 certstrap if
- You want the certstrap 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 certstrap 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 certstrap
certstrap is a simple certificate manager written in Go that bootstraps a private certificate authority and public key infrastructure, aimed at operators and developers who need to issue TLS certificates without wrestling with openssl.
read the full certstrap overview →
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Frequently asked questions
Is Signal or certstrap more popular?
Signal has 29,359 GitHub stars and certstrap has 2,454. Signal has the larger community by that measure.
Are Signal and certstrap free?
Both are open source. Signal is licensed under AGPL-3.0 and certstrap under Apache-2.0. Neither carries a licence fee.
What is the difference between Signal and certstrap?
Signal is written in Kotlin and certstrap 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 certstrap?
Choose Signal if you want the larger community (29,359 stars) or its AGPL-3.0 licence terms. Choose certstrap if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.