HOL Light vs Why3
| HOL Light | Why3 | |
|---|---|---|
| Free plan | No | Yes |
| Free trial | No | No |
| Paid from | — | Free |
| Open source | No | No |
| Platforms | Linux, macOS, self-hosted, Web, Windows | api, Linux, self-hosted, Web, Windows |
| Free plan | Yes | — |
| Verification method | deductive | deductive |
| Supported formalisms | theorem-proving | contracts |
| Input languages | OCaml; higher-order logic | WhyML, micro-C, micro-Python, MLCFG, Coma |
| Deployment | self-hosted | both |
| Counterexamples | — | Yes |
Both are listed in Best Formal Verification Tools. On Freedom251, HOL Light scores higher on our published basis.