Best Formal Verification Tools in 2026
Updated
In short: Z3 is ranked #1 of 33 as of 4 October 2026, ahead of PVS and Rocq. The best-ranked option with a free plan is PVS.
Formal verification tools help you reason about whether software satisfies specified properties. Compare supported formalisms and input languages to understand what each tool can address, then look at verification method, counterexamples, and proof artifacts to see how results are established and represented. Deployment options, free-plan availability, and paid-from pricing offer further distinctions. In the ranking, Z3 leads the entries, followed by Rocq and Isabelle. PVS, ACL2, Frama-C, K Framework, and Dafny are also among the first tools shown. Use these details to consider how each option fits your specifications and the evidence you need from verification.
33 formal verification tools ranked on what their makers publish — plans and prices, free tiers, platforms and the facts on their own pages.
Recognised 40% · Phone app 26% · Documented 20% · Free plan 14% of the score
- 1 Z3 Android only RecognisedPhone appDocumentedFree plan 7.8Free Supported formalisms: theorem-provingCounterexamples: Yes
- 2 PVS No phone app RecognisedPhone appDocumentedFree plan 6.4Free Verification method: hybridSupported formalisms: theorem-provingCounterexamples: Yes
- 3 Rocq No phone app RecognisedPhone appDocumentedFree plan 6.4Free Verification method: deductiveSupported formalisms: theorem-proving
- 4 Alloy Analyzer No phone app RecognisedPhone appDocumentedFree plan 6.3Free Verification method: model-checkingSupported formalisms: invariantsCounterexamples: Yes
- 5 Isabelle No phone app RecognisedPhone appDocumentedFree plan 6.3Free Verification method: deductiveSupported formalisms: theorem-provingCounterexamples: Yes
- 6 SPIN No phone app RecognisedPhone appDocumentedFree plan 6.3Free Verification method: model-checkingSupported formalisms: temporal-logicCounterexamples: Yes
- 7 UPPAAL No phone app RecognisedPhone appDocumentedFree plan 6.3Free Verification method: model-checkingSupported formalisms: invariantsCounterexamples: Yes
- 8 ACL2 No phone app RecognisedPhone appDocumentedFree plan 5.8 Verification method: deductiveSupported formalisms: theorem-provingCounterexamples: Yes
- 9 Frama-C No phone app RecognisedPhone appDocumentedFree plan 5.8 Verification method: hybridSupported formalisms: contractsCounterexamples: Yes
- 10 CPAchecker No phone app RecognisedPhone appDocumentedFree plan 5.4 Verification method: hybridSupported formalisms: invariantsCounterexamples: Yes
- 11 Viper No phone app RecognisedPhone appDocumentedFree plan 5.4 Verification method: hybridSupported formalisms: contractsCounterexamples: Yes
- 12 Apalache No phone app RecognisedPhone appDocumentedFree plan 5.3 Verification method: symbolicSupported formalisms: invariantsCounterexamples: Yes
- 13 CBMC No phone app RecognisedPhone appDocumentedFree plan 5.3 Verification method: model-checkingSupported formalisms: contractsCounterexamples: Yes
- 14 Dafny No phone app RecognisedPhone appDocumentedFree plan 5.3 Verification method: deductiveSupported formalisms: contractsCounterexamples: Yes
- 15 HOL Light No phone app RecognisedPhone appDocumentedFree plan 5.3 Verification method: deductiveSupported formalisms: theorem-proving
- 16 HOL4 No phone app RecognisedPhone appDocumentedFree plan 5.3 Supported formalisms: theorem-provingCounterexamples: Yes
- 17 K Framework No phone app RecognisedPhone appDocumentedFree plan 5.3 Verification method: hybridSupported formalisms: theorem-proving
- 18 Lean No phone app RecognisedPhone appDocumentedFree plan 5.3 Verification method: deductiveSupported formalisms: theorem-proving
- 19 NuSMV No phone app RecognisedPhone appDocumentedFree plan 5.3 Verification method: hybridSupported formalisms: temporal-logicCounterexamples: Yes
- 20 OpenJML No phone app RecognisedPhone appDocumentedFree plan 5.3 Verification method: deductiveSupported formalisms: contractsCounterexamples: Yes
- 21 PRISM No phone app RecognisedPhone appDocumentedFree plan 5.3 Verification method: symbolicSupported formalisms: temporal-logicCounterexamples: Yes
- 22 Romeo No phone app RecognisedPhone appDocumentedFree plan 5.3 Verification method: model-checkingSupported formalisms: temporal-logic
- 23 Satisfiability.jl No phone app RecognisedPhone appDocumentedFree plan 5.3 Verification method: symbolicSupported formalisms: theorem-proving
- 24 SeaHorn No phone app RecognisedPhone appDocumentedFree plan 5.3 Verification method: hybridSupported formalisms: invariantsCounterexamples: Yes
- 25 Stainless No phone app RecognisedPhone appDocumentedFree plan 5.3 Verification method: deductiveSupported formalisms: contractsCounterexamples: Yes
Is your app on this list?
Numbered spots on this list can be sponsored. They are labelled, and the editorial order and scores never change for payment.
Questions about this list
Which formal verification tool is ranked first on Samsung Mobile US Press?
Z3 is ranked #1 of 33 with a score of 7.8. PVS is second and Rocq third.
How many of these have a free plan?
7 of the 25 on this page publish a free plan on their own pricing pages.
How is this list ranked?
Ranked mobile-first: a phone app alongside the web or desktop product, a free tier and the depth of its documentation. Paid placements never change a rank.