Best Formal Verification Tools in 2026
Updated
Formal verification tools help you reason about whether a system satisfies specified properties. Compared on supported formalisms and input languages, they can be assessed for what they let you model; verification method, counterexamples and proof artifacts indicate how results and evidence are represented. Deployment, free-plan availability and paid-from pricing add practical dimensions. Alloy Analyzer, Z3 and PVS are among the tools shown. As you evaluate them, consider the kinds of specifications your work needs to express and what evidence your team expects to review.
Formal Verification Tools, one module each.A lit port is something its maker publishes; 7 of 7 with a known API signal have a public API.
- 01 cvc5 API yesFREE yesDOCS 7.4Free
- 02 Why3 API yesFREE yesDOCS 7.4Free
- 03 Alloy Analyzer API yesFREE yesDOCS 7.3Free
- 04 Z3 API yesFREE yesDOCS 7.3Free
- 05 OpenJML API yesFREE yesDOCS 7.2Free
- 06 K Framework API yesDOCS 7.0
- 07 Apalache API yesDOCS 6.9
- 08 Boogie FREE yesDOCS 6.0Free
- 09 HOL4 FREE yesDOCS 6.0Free
- 10 Lean FREE yesDOCS 6.0Free
- 11 PVS FREE yesDOCS 6.0Free
- 12 Rocq FREE yesDOCS 6.0Free
- 13 CBMC FREE yesDOCS 5.9Free
- 14 CPAchecker FREE yesDOCS 5.9Free
- 15 Isabelle FREE yesDOCS 5.9Free
- 16 NuSMV FREE yesDOCS 5.9Free
- 17 PRISM FREE yesDOCS 5.9Free
- 18 SPIN FREE yesDOCS 5.9Free
- 19 UPPAAL FREE yesDOCS 5.9Free
- 20 VeriFast FREE yesDOCS 5.9Free
- 21 F* FREE yesDOCS 5.8Free
- 22 TLA+ FREE yesDOCS 5.8Free
- 23 ACL2 DOCS 5.6
- 24 Agda DOCS 5.6
- 25 Dafny DOCS 5.6
Compare all 25 in a table
| # | Platform | Score | Free plan | From | Free plan | Paid from | Verification method | Supported formalisms |
|---|---|---|---|---|---|---|---|---|
| 1 | cvc5 | 7.4 | Free plan | Free | theorem-proving | |||
| 2 | Why3 | 7.4 | Free plan | Free | deductive | contracts | ||
| 3 | Alloy Analyzer | 7.3 | Free plan | Free | Yes | model-checking | invariants | |
| 4 | Z3 | 7.3 | Free plan | Free | Yes | theorem-proving | ||
| 5 | OpenJML | 7.2 | Free plan | Free | deductive | contracts | ||
| 6 | K Framework | 7.0 | Yes | hybrid | theorem-proving | |||
| 7 | Apalache | 6.9 | symbolic | invariants | ||||
| 8 | Boogie | 6.0 | Free plan | Free | deductive | contracts | ||
| 9 | HOL4 | 6.0 | Free plan | Free | Yes | theorem-proving | ||
| 10 | Lean | 6.0 | Free plan | Free | deductive | theorem-proving | ||
| 11 | PVS | 6.0 | Free plan | Free | Yes | hybrid | theorem-proving | |
| 12 | Rocq | 6.0 | Free plan | Free | Yes | deductive | theorem-proving | |
| 13 | CBMC | 5.9 | Free plan | Free | Yes | model-checking | contracts | |
| 14 | CPAchecker | 5.9 | Free plan | Free | hybrid | invariants | ||
| 15 | Isabelle | 5.9 | Free plan | Free | Yes | deductive | theorem-proving | |
| 16 | NuSMV | 5.9 | Free plan | Free | Yes | hybrid | temporal-logic | |
| 17 | PRISM | 5.9 | Free plan | Free | Yes | symbolic | temporal-logic | |
| 18 | SPIN | 5.9 | Free plan | Free | Yes | model-checking | temporal-logic | |
| 19 | UPPAAL | 5.9 | Free plan | Free | Yes | model-checking | invariants | |
| 20 | VeriFast | 5.9 | Free plan | Free | symbolic | contracts | ||
| 21 | F* | 5.8 | Free plan | Free | hybrid | theorem-proving | ||
| 22 | TLA+ | 5.8 | Free plan | Free | hybrid | invariants | ||
| 23 | ACL2 | 5.6 | Yes | deductive | theorem-proving | |||
| 24 | Agda | 5.6 | deductive | theorem-proving | ||||
| 25 | Dafny | 5.6 | Yes | deductive | contracts |
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