# ProvableHQ/leo

🦁 The Leo Programming Language. A Programming Language for Formally Verified, Zero-Knowledge Applications

Repository: https://github.com/ProvableHQ/leo
Canonical: https://ross.abutalabs.com/products/leo
Homepage: https://leo-lang.org/
Language: Rust
License: GPL-3.0
License Family: copyleft
Topics: programming-language, zero-knowledge, compiler, zksnarks, leo
Last push: 2026-08-19T18:28:10+00:00

## Health v2 (maintenance only)
Score: 98/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 98, release rhythm 98, longevity 100
- inputs: {"age_days": 2367, "days_push": 14, "days_rel": 14, "gap_med": 5.0, "n_releases_24m": 49}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 4821, forks 716 (observed 2026-08-28T04:09:00.533560+00:00)

## What it is
Leo is an imperative, statically-typed programming language for writing zero-knowledge applications that compile to circuits for the Aleo blockchain. It ships as a Rust-based toolchain including a compiler, CLI, formatter, and language server, with unit and integration testing support.

## Use cases
- write zero-knowledge applications
- compile programs to zk circuits
- build private apps on the Aleo blockchain
- learn a zero-knowledge programming language
- test and format Leo smart programs
- develop privacy-preserving blockchain contracts

## When to choose
- you are building private, zero-knowledge applications on Aleo
- you want a high-level language that abstracts circuit and cryptographic details
- you need tooling like LSP, formatter, and tests for zk development

## When to avoid
- you need a general-purpose programming language outside zero-knowledge contexts
- you target blockchains other than Aleo
- you need a fully stable language, since Leo is still subject to breaking changes

## Facets
- artifact type: cli-tool
- maturity: active
- function: programming-language, compiler, cli, testing, cryptography
- domain: programming-languages, blockchain, developer-tools, privacy
- platform: windows, rust, cli
- tags: zero-knowledge, zk-snarks, aleo, statically-typed, private-applications, lsp, formatter, cryptography, linux, macos

## Member repositories
- ProvableHQ/leo (main) score 98

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:09:00.533560+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T18:18:31.830483+00:00, confidence not recorded.
  - readme: https://github.com/ProvableHQ/leo (fetched 2026-08-28T04:09:00.533560+00:00, sha 1a2ae09ebea7)
  - homepage: https://leo-lang.org/ (fetched 2026-08-29T09:01:27.778956+00:00, sha 87405bc538d5)
  - site_page: https://docs.leo-lang.org (fetched 2026-08-29T09:01:27.781690+00:00, sha 0067a627d371)
- Data as of 2026-08-30T08:39:29.467469+00:00.