Lean Lean

Open-source Lean projects categorized as Lean

Top 5 Lean Lean Projects

  1. lean4

    Lean 4 programming language and theorem prover

    Project mention: Lean 4, Release v4.17.0 | news.ycombinator.com | 2025-03-04
  2. Stream

    Stream - Scalable APIs for Chat, Feeds, Moderation, & Video. Stream helps developers build engaging apps that scale to millions with performant and flexible Chat, Feeds, Moderation, and Video APIs and SDKs powered by a global edge network and enterprise-grade infrastructure.

    Stream logo
  3. batteries

    The "batteries included" extended library for the Lean programming language and theorem prover (by leanprover-community)

  4. ProofWidgets4

    Helper toolkit for creating your own Lean 4 UserWidgets

    Project mention: Why Fennel? | news.ycombinator.com | 2025-04-13

    > I’d rather have the language …

    check out Lean 4 then. Its syntax system is based on Racket but —instead of parens— implements stuff like [JSX syntax](https://github.com/leanprover-community/ProofWidgets4/blob/d...) and a [maze](https://github.com/dwrensha/lean4-maze)

  5. hott3

    HoTT in Lean 3

  6. ground_zero

    Ground Zero: Lean 4 HoTT Library

    Project mention: Should Type Theory (HoTT) Replace (ZFC) Set Theory as the Foundation of Math? | news.ycombinator.com | 2025-02-27
  7. InfluxDB

    InfluxDB – Built for High-Performance Time Series Workloads. InfluxDB 3 OSS is now GA. Transform, enrich, and act on time series data directly in the database. Automate critical tasks and eliminate the need to move data externally. Download now.

    InfluxDB logo
NOTE: The open source projects on this list are ordered by number of github stars. The number of mentions indicates repo mentiontions in the last 12 Months or since we started tracking (Dec 2020).

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Index

What are some of the best open-source Lean projects in Lean? This list will help you:

# Project Stars
1 lean4 5,941
2 batteries 312
3 ProofWidgets4 146
4 hott3 79
5 ground_zero 63

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Did you know that Lean is
the 64th most popular programming language
based on number of references?