Lean is a functional programming language and interactive theorem prover based on dependent type theory. Dependent type theory unites the worlds of programs and proofs; thus, Lean is also a programming language.
Cost / License
- Free
- Open Source
Application type
Platforms
- Mac
- Windows
- Linux
- Visual Studio Code
Lean Prover is the most popular Windows, Mac & Linux alternative to Rocq Prover.
Lean Prover is the most popular Open Source & free alternative to Rocq Prover.
- Lean Prover is Free and Open Source










Its logic is weaker (simply-typed HOL), but its tooling is much more developed: Prover IDE, integration of automated reasoning systems via Sledgehammer, many add-on tools, big Archive of Formal Proofs