Best Stainless Alternatives in 2026
Updated
20 apps from formal verification tools ranked against Stainless on the same published basis.
- 1Stainless vs Z3
- 2Stainless vs HOL4
- 3Stainless vs PVS
- 4Stainless vs Rocq
- 5Stainless vs Alloy Analyzer
- 6Stainless vs CBMC
- 7Stainless vs Isabelle
- 8Stainless vs NuSMV
- 9Stainless vs PRISM
- 10Stainless vs SPIN
- 11Stainless vs UPPAAL
- 12Stainless vs ACL2
- 13Stainless vs Dafny
- 14Stainless vs Frama-C
- 16Stainless vs HOL Light
- 17Stainless vs Ultimate Automizer
- 18Stainless vs Boogie
- 19Stainless vs CPAchecker
- 20Stainless vs Viper
- 21Stainless vs Apalache
Stainless alternatives compared
| # | App | Score | Free plan | From | Runs on |
|---|---|---|---|---|---|
| 1 | Z3 | 7.8 | Free plan | Free | Android, API, Linux, Mac, self-hosted, Web, Windows |
| 2 | HOL4 | 6.4 | Free plan | Free | Linux, Mac, self-hosted, Windows |
| 3 | PVS | 6.4 | Free plan | Free | Linux, Mac, Windows |
| 4 | Rocq | 6.4 | Free plan | Free | Browser, Linux, Mac, Web, Windows |
| 5 | Alloy Analyzer | 6.3 | Free plan | Free | API, Linux, Mac, Windows |
| 6 | CBMC | 6.3 | Free plan | Free | Linux, Mac, self-hosted, Windows |
| 7 | Isabelle | 6.3 | Free plan | Free | Linux, Mac, self-hosted, Windows |
| 8 | NuSMV | 6.3 | Free plan | Free | Linux, Mac, Windows |
| 9 | PRISM | 6.3 | Free plan | Free | Linux, Mac, Windows |
| 10 | SPIN | 6.3 | Free plan | Free | Linux, Mac, Windows |
| 11 | UPPAAL | 6.3 | Free plan | Free | Linux, Mac, Windows |
| 12 | ACL2 | 5.8 | No | — | Linux, Mac, self-hosted, Windows |
| 13 | Dafny | 5.8 | No | — | Linux, Mac, self-hosted, Windows |
| 14 | Frama-C | 5.8 | No | — | Linux, Mac, Windows |
| 16 | HOL Light | 5.7 | No | — | Linux, Mac, self-hosted, Web, Windows |
| 17 | Ultimate Automizer | 5.7 | No | — | Linux, Web, Windows |
| 18 | Boogie | 5.6 | No | — | — |
| 19 | CPAchecker | 5.4 | Free plan | Free | Linux, Mac, self-hosted, Windows |
| 20 | Viper | 5.4 | No | — | Windows, Mac, Linux |
| 21 | Apalache | 5.3 | No | — | — |
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Questions about Stainless alternatives
What is the best alternative to Stainless?
Z3, number 1 in formal verification tools with a score of 7.8 out of 10. The others here: HOL4, PVS, Rocq and 16 more.
What is the best free alternative to Stainless?
Z3 is the best-ranked alternative with a free plan. 12 of the 20 alternatives here publish a free plan on their own pricing pages.
How are these alternatives ranked?
Ranked mobile-first: a phone app alongside the web or desktop product, a free tier and the depth of its documentation.