# erg-lang/erg

A statically typed language compatible with Python

Repository: https://github.com/erg-lang/erg
Canonical: https://ross.abutalabs.com/products/erg
Homepage: http://erg-lang.org
Language: Rust
License: Apache-2.0
License Family: permissive
Topics: compiler, programming-language, python, rust, language, erg, transpiler
Last push: 2025-12-04T02:20:50+00:00

## Health v2 (maintenance only)
Score: 59/100 (v2, computed 2026-09-03T02:39:23.370411+00:00)
- activity 55, release rhythm 42, longevity 100
- inputs: {"age_days": 1484, "days_push": 273, "days_rel": 386, "gap_med": 17.5, "n_releases_24m": 11}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2860, forks 61 (observed 2026-08-28T04:07:26.042443+00:00)

## What it is
Erg is a statically typed, Python-compatible general-purpose programming language with a powerful type system featuring dependent and refinement types. Its compiler, written in Rust, transpiles Erg code to Python bytecode, giving zero-cost access to the Python ecosystem.

## Use cases
- write statically typed code that interoperates with Python
- catch null errors and out-of-bounds array access at compile time
- gradually replace Python scripts while keeping Python libraries
- use dependent and refinement types to encode preconditions
- get a Rust-like robust language without verbose type annotations
- transpile code to Python bytecode for CPython compatibility

## When to choose
- you want stronger compile-time guarantees than Python offers but need Python library access
- you want an ML-like simple, consistent syntax with powerful type inference
- you want side-effect tracking and maintainability markers in the language
- you want a multi-paradigm functional/OOP language with friendly error messages

## When to avoid
- you need a mature, production-proven language with a large ecosystem
- you rely on features listed as not yet implemented in the project's TODO
- your team is heavily invested in dynamic Python tooling and workflows
- you need guaranteed stability across releases, as the language is still evolving

## Facets
- artifact type: cli-tool
- maturity: active
- function: compiler, programming-language, type-system, interpreter, cli
- domain: programming-languages, compilers, developer-tools
- platform: windows, rust, python, cross-platform, cli
- tags: statically-typed, python-interop, transpiler, dependent-types, refinement-types, language-server, repl, linux, macos

## Member repositories
- erg-lang/erg (main) score 59

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:07:26.042443+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 2026-08-30T08:13:01.148141+00:00, confidence not recorded.
  - readme: https://github.com/erg-lang/erg (fetched 2026-08-28T04:07:26.042443+00:00, sha 37ccacd5cf06)
  - homepage: http://erg-lang.org (fetched 2026-08-29T09:52:09.376109+00:00, sha 0a41bd2d5be4)
  - site_page: https://erg-lang.org/docs (fetched 2026-08-29T09:52:09.385745+00:00, sha 16537f6590c6)
  - site_page: https://erg-lang.org/install (fetched 2026-08-29T09:52:09.388545+00:00, sha 39f9ef47f74e)
- Data as of 2026-08-30T08:39:29.467469+00:00.