Products

Lean

Open-source programming language and proof assistant that enables correct, maintainable, and formally verified code

lean-lang.org Source★ 1,797Apache-2.0Software Development / Developer Utilities

AI Benchmark
Desktop
Mobile
Monthly visits
256.1K
Down10.2%MoMOct 2026
Public revenue
Undisclosed
No public revenue evidence yet
Entry price
Free
No monthly subscription pricing
Creators
leanprover
@leanprover· 14.6K followers
Launched
3y ago
2023-09-05 · Est.

Traffic

Monthly visitsData through Oct 2026
Events2 changes

Marketing moves

Launches, search & content, referrals, promotions
  • New product launchLaunch

    Sep 5, 2023 · 3y agoWebsite

Open Source & Self-Hosting

GitHub · MCP / Skill
Last commit 2026-11-07
GitHub Stars
★ 1,797
Forks
259
License
Apache-2.0
Primary language
Go

Traffic sources

Oct 2026

Traffic breakdown

Channels

  • Organic Search55%
  • Direct31%
  • Referrals9%
  • Other5%

Countries

  • United States24%
  • India14%
  • United Kingdom9%
  • Germany6%
  • Canada4%

Search

Domain authority —Domain registered 2023-09-05

KeywordMonthly volume
lean178.2K
lean programming language11K
lean math6,940
lean 43,890
lean language3,750

Traffic data: Vaneform

Pricing

Pricing page not identified yet, or no public pricing listed.

Pages & changes

Tracked since 2026-11-04

Key pages

Weekly snapshots
lean-lang.org/ Snapshot 2026-11-05

Changes

  1. Nov 1 · 14d ago

    Homepage headline (H1) changed to “Get Started with Lean”Positioning

    Lean in Action→Get Started with Lean

    At the time: 256.1K visits/mo1 concurrent move
  2. Nov 1 · 14d ago

    Homepage title changed to “Lean Programming Language”Positioning

    Lean enables correct, maintainable, and formally verified code→Lean Programming Language

    At the time: 256.1K visits/mo1 concurrent move

Design

First-screen visual analysis & :root CSS

Minimal Monochrome (Light canvas, airy density) featuring split copy & visual layout and code block / terminal / cli visuals.

First-screen preview · click to zoom

First-screen pitch & conversion flow

“Lean is an open-source programming language and proof assistant that enables correct, maintainable, and formally verified code”

Split Copy & Visual hero structure paired with start free / sign up CTA and no explicit trust bar.

Conversion path: Split Copy & Visual + Code Block / Terminal / CLI → Start Free / Sign Up

Palette · click to copy

5-D design score7.1 / 10
Typography
7.0
Color & Contrast
7.0
Layout & Spacing
8.0
Craft & Polish
7.0
Distinctiveness
6.0

Structure

Fonts
Inter / JetBrains Mono
Primary visual
Code Block / Terminal / CLI
Conversion CTA
Start Free / Sign Up
Social proof
No Explicit Trust Bar
Navigation
Full-Width Top Bar
Theme & density
Light · Airy
Corners & depth
Medium Radius · With shadow
Preview full AI design brief (includes :root CSS variables & layout rules)Style tokens only; never copy brand names, logos, copy, or images
# Design Brief: Minimal Monochrome

Monochrome palette with a single accent color, hairline dividers, and generous whitespace.

## Design Tokens

```css
:root {
  --background: #f4f7fb;
  --surface: #ffffff;
  --foreground: #1a1d24;
  --muted-foreground: #6b7280;
  --accent: #2f6fed;
  --radius: 8px;
  --font-heading: "Inter", ui-sans-serif, system-ui, sans-serif;
  --font-body: "Inter", ui-sans-serif, system-ui, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, monospace;
}
```

Color area ratio: Background #F4F7FB (~46%) · Surface #FFFFFF (~28%) · Text #1A1D24 (~12%) · Muted Text #6B7280 (~6%) · Accent #2F6FED (~8%). Background and surface dominate the canvas; reserve the accent color for primary buttons and active states.

## Layout & Conversion Structure

- Hero layout: Split Copy & Visual
- Navigation: Full-Width Top Bar
- Theme & density: Light · Airy
- Border radius & elevation: Medium Radius; use elevation shadows to separate layers
- Primary visual medium: Code Block / Terminal / CLI
- Conversion CTA: Start Free / Sign Up
- Headline hook: Category Positioning Anchor
- Hero components: Code & Terminal, Large Hero Product Shot
- Spatial layout notes: Split Copy & Visual hero structure paired with start free / sign up CTA and no explicit trust bar.
- Visual summary: Minimal Monochrome (Light canvas, airy density) featuring split copy & visual layout and code block / terminal / cli visuals.

## Avoid

- Multi-stop neon gradients
- Heavy drop shadows
- More than one competing accent color

Implement the UI following the design tokens and layout specifications above: use only these color variables, and reserve the accent color strictly for primary actions and active states. Adopt only this visual style—never copy any reference product’s brand name, logo, copy, or imagery.

Questions & evidence

How much website traffic does Lean get?
Vaneform estimates 256.1K website visits in 2026-10. Visits can include repeat visits; this estimate measures web traffic separately from paying customers or revenue.Source
What is Lean and what platforms does it support?
Lean is catalogued under Developer Utilities: Open-source programming language and proof assistant that enables correct, maintainable, and formally verified code. Supported platforms: Web.
Is Lean open source?
Lean has a public repository (https://github.com/leanprover/lean4) under the Apache-2.0 license, recording 1,797 GitHub stars.Source

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