Best Stainless Alternatives in 2026
Updated
20 tools from formal verification tools ranked against Stainless on the same published basis.
- 1Stainless vs Lean
- 2Stainless vs PVS
- 3Stainless vs Rocq
- 4Stainless vs Z3
- 5Stainless vs HOL4
- 6Stainless vs Alloy Analyzer
- 7Stainless vs NuSMV
- 8Stainless vs UPPAAL
- 9Stainless vs CBMC
- 10Stainless vs CPAchecker
- 11Stainless vs HOL Light
- 12Stainless vs Isabelle
- 13Stainless vs PRISM
- 14Stainless vs SPIN
- 15Stainless vs ACL2
- 16Stainless vs Viper
- 17Stainless vs Frama-C
- 19Stainless vs Dafny
- 20Stainless vs K Framework
- 21Stainless vs Ultimate Automizer
Stainless alternatives compared
| # | Tool | Score | Free plan | From | Runs on |
|---|---|---|---|---|---|
| 1 | Lean | 7.5 | Free plan | Free | Linux, Mac, Web, Windows |
| 2 | PVS | 7.5 | Free plan | Free | Linux, Mac, Windows |
| 3 | Rocq | 7.5 | Free plan | Free | Browser, Linux, Mac, Web, Windows |
| 4 | Z3 | 7.4 | Free plan | Free | Android, API, Linux, Mac, self-hosted, Web, Windows |
| 5 | HOL4 | 7.3 | Free plan | Free | Linux, Mac, self-hosted, Windows |
| 6 | Alloy Analyzer | 7.2 | Free plan | Free | API, Linux, Mac, Windows |
| 7 | NuSMV | 7.2 | Free plan | Free | Linux, Mac, Windows |
| 8 | UPPAAL | 7.2 | Free plan | Free | Linux, Mac, Windows |
| 9 | CBMC | 7.1 | Free plan | Free | Linux, Mac, self-hosted, Windows |
| 10 | CPAchecker | 7.1 | Free plan | Free | Linux, Mac, self-hosted, Windows |
| 11 | HOL Light | 7.1 | No | — | Linux, Mac, self-hosted, Web, Windows |
| 12 | Isabelle | 7.1 | Free plan | Free | Linux, Mac, self-hosted, Windows |
| 13 | PRISM | 7.1 | Free plan | Free | Linux, Mac, Windows |
| 14 | SPIN | 7.1 | Free plan | Free | Linux, Mac, Windows |
| 15 | ACL2 | 7.0 | No | — | Linux, Mac, self-hosted, Windows |
| 16 | Viper | 7.0 | No | — | Browser, Linux, Mac, Web, Windows |
| 17 | Frama-C | 6.9 | No | — | Linux, Mac, Windows |
| 19 | Dafny | 6.8 | No | — | Linux, Mac, self-hosted, Windows |
| 20 | K Framework | 6.8 | No | — | API, Linux, Mac, self-hosted |
| 21 | Ultimate Automizer | 6.7 | No | — | Linux, Web, Windows |
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Questions about Stainless alternatives
What is the best alternative to Stainless?
Lean, number 1 in formal verification tools with a score of 7.5 out of 10. The others here: PVS, Rocq, Z3 and 16 more.
What is the best free alternative to Stainless?
Lean is the best-ranked alternative with a free plan. 13 of the 20 alternatives here publish a free plan on their own pricing pages.
How are these alternatives ranked?
Ranked on what each maker publishes, the fullest spec sheet first: how deeply the product is documented, the platforms it runs on, a free tier or trial to test it, and its standing.