Best Isabelle Alternatives in 2026
Updated
20 apps from formal verification tools ranked against Isabelle on the same published basis.
- 1Isabelle vs Rocq
- 2Isabelle vs PVS
- 3Isabelle vs Z3
- 5Isabelle vs SPIN
- 6Isabelle vs UPPAAL
- 7Isabelle vs Alloy Analyzer
- 8Isabelle vs CBMC
- 9Isabelle vs ACL2
- 10Isabelle vs Dafny
- 11Isabelle vs Frama-C
- 12Isabelle vs Ultimate Automizer
- 13Isabelle vs HOL Light
- 14Isabelle vs Lean
- 15Isabelle vs CPAchecker
- 16Isabelle vs cvc5
- 17Isabelle vs NuSMV
- 18Isabelle vs PRISM
- 19Isabelle vs Stainless
- 20Isabelle vs Viper
- 21Isabelle vs Agda
Isabelle alternatives compared
| # | App | Score | Free plan | From | Runs on |
|---|---|---|---|---|---|
| 1 | Rocq | 7.4 | Free plan | Free | Browser, Linux, Mac, Web, Windows |
| 2 | PVS | 7.3 | Free plan | Free | Linux, Mac, Windows |
| 3 | Z3 | 7.3 | Free plan | Free | Android, API, Linux, Mac, self-hosted, Web, Windows |
| 5 | SPIN | 7.1 | Free plan | Free | Linux, Mac, Windows |
| 6 | UPPAAL | 7.1 | Free plan | Free | Linux, Mac, Windows |
| 7 | Alloy Analyzer | 7.0 | Free plan | Free | API, Linux, Mac, Windows |
| 8 | CBMC | 7.0 | Free plan | Free | Linux, Mac, self-hosted, Windows |
| 9 | ACL2 | 6.6 | No | — | Linux, Mac, self-hosted, Windows |
| 10 | Dafny | 6.6 | No | — | Linux, Mac, self-hosted, Windows |
| 11 | Frama-C | 6.6 | No | — | Linux, Mac, Windows |
| 12 | Ultimate Automizer | 6.4 | No | — | Linux, Web, Windows |
| 13 | HOL Light | 6.1 | No | — | Web, Windows, Mac, Linux |
| 14 | Lean | 6.1 | No | — | Web, Windows, Mac, Linux |
| 15 | CPAchecker | 6.0 | No | — | Windows, Mac, Linux |
| 16 | cvc5 | 6.0 | No | — | Web, Windows, Mac, Linux |
| 17 | NuSMV | 6.0 | Free plan | Free | Linux, Mac, Windows |
| 18 | PRISM | 6.0 | No | — | Windows, Mac, Linux |
| 19 | Stainless | 6.0 | No | — | Windows, Mac, Linux |
| 20 | Viper | 6.0 | No | — | Windows, Mac, Linux |
| 21 | Agda | 5.9 | No | — | Windows, Mac, Linux |
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Questions about Isabelle alternatives
What is the best alternative to Isabelle?
Rocq, number 1 in formal verification tools with a score of 7.4 out of 10. The others here: PVS, Z3, SPIN and 16 more.
What is the best free alternative to Isabelle?
Rocq is the best-ranked alternative with a free plan. 8 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: documentation depth, a free tier and the platforms it runs on.