Lean is a functional programming language that makes it easy to write correct and maintainable code. You can also use Lean as an interactive theorem prover. Lean programming primarily involves defining types and functions. This allows your focus to remain on the problem domain and manipulating its data, rather than the details of programming. Lean has numerous features, including:
- Type inference
- First-class functions
- Powerful data types
- Pattern matching
- Type classes
- Extensible syntax
- Hygienic macros
- Dependent types
- Metaprogramming framework
- Multithreading
- Verification: you can prove properties of your functions using Lean itself
Publisher’s description
What is Lean?
Lean by Lean FRO is open-source Windows software in the ides & code editors category. It is written in Lean.
Installation and requirements
The publisher provides Portable installers for 64-bit Windows. It runs without installation (portable).
Updates and version history
The current version is 4.35.0, released on October 12, 2026. The version history goes back to May 1, 2025: 24 releases, all linked to the official files. That is about 17 releases a year. The last update is less than a month old.
Popularity and file types
The source code on GitHub (leanprover/lean4) has 9,626 stars. Similar programs include OpenCode, RStudio and Node.js (LTS).
Project description on GitHub: “Lean 4 programming language and theorem prover”
Pros / Cons
Pros
- Open source: the code can be inspected and built by anyone
- Portable: runs without installation
- Frequent updates (about 17 a year)
- Large user base
Cons
- No native ARM64 build
In short: Lean is an open-source ides & code editor tool for 64-bit PCs. It is actively maintained.
Is Lean safe to download?
- The file is served by github.com, the publisher’s own domain
- The download link uses HTTPS
- A SHA256 hash is published, so you can verify the file:
5FC033E93E1A7BC59C5EBF311103D2C9CD18D4B3EDDDA4FFA3414E8ADB0EF79E· Open the VirusTotal report for this hash - The link has not been checked yet
- The source code is public
- ExeAtlas does not host, wrap or modify installers
Related guide: How to check a file’s SHA256 hash on Windows
Security practices (OpenSSF Scorecard)
Automated checks of the leanprover/lean4 repository on GitHub by the Open Source Security Foundation, last run on October 19, 2026.
- Actively maintained10
- No dangerous workflows10
- Licence declared10
- No binaries in the repository10
- Pinned dependencies4
- Code review1
- Restricted token permissions0
- OpenSSF Best Practices badge0
- Security policy0
- Fuzzing0
- Signed releases0
- Static code analysis0
The score rates how the project is developed and released, not whether the program is safe to install. scorecard.dev
Recent versions
All 24 versions ›24 versions over 1 year · about 17 a year
| Version | Date | Size | Files |
|---|---|---|---|
| 4.35.0Latest | October 12, 2026 | — | 64-bit ZIP |
| 4.34.1 | September 24, 2026 | — | 64-bit ZIP |
| 4.34.0 | September 14, 2026 | — | 64-bit ZIP |
| 4.33.1 | August 21, 2026 | — | 64-bit ZIP |
| 4.33.0 | August 10, 2026 | — | 64-bit ZIP |
| 4.32.2 | July 28, 2026 | — | 64-bit ZIP |
| 4.32.1 | July 22, 2026 | — | 64-bit ZIP |
| 4.32.0 | July 13, 2026 | — | 64-bit ZIP |
Install from the command line
Silent install ›winget install --id Lean.Lean -eProgram files (.exe): lean.exe, leanc.exe
Related guide: How to use winget: install and update apps
Information
- Publisher
- Lean FRO
- Category
- IDEs & code editors
- Licence
- Apache-2.0
- Price
- Free
- Source code
- github.com/leanprover/lean4
- Written in
- Lean
- Requires
- Windows 11 / 10
- Architecture
- 64-bit
- Installer
- Portable
- Version
- 4.35.0
- Released
- October 12, 2026
- Added to the catalogue
- May 6, 2025
- Versions listed
- 24
- Updates / year
- 16.6
- GitHub stars
- 9,626
- GitHub forks
- 1,059
- Website
- lean-lang.org
- winget ID
- Lean.Lean
Ratings and reviews
No reviews yet. Be the first to rate it.
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Frequently asked questions
Is Lean free?
Yes. Lean is open-source software under the Apache-2.0 licence.
Is Lean safe to download?
The download comes from github.com, which belongs to the publisher; ExeAtlas does not host or change the file. Compare its SHA256 hash with the one shown here, or open the VirusTotal report for that hash.
How do I install Lean with winget?
Open PowerShell or Windows Terminal and run the winget command shown on this page. winget downloads the official installer and checks its SHA256 hash before running it.
Does Lean run on ARM (Windows on Arm)?
There is no ARM64 build; Windows 11 on Arm can run the 64-bit version through emulation.
Where can I download an older version of Lean?
The versions page lists all 24 versions with links to their official installer files, back to May 1, 2025.
Can I use Lean without administrator rights?
Yes, it is portable: unpack and run it.
What are alternatives to Lean?
OpenCode, RStudio, Node.js (LTS), Apache NetBeans and Haxe. The alternatives page compares them.
