# soutaro/steep

Static type checker for Ruby

Repository: https://github.com/soutaro/steep
Canonical: https://ross.abutalabs.com/products/steep
Language: Ruby
License: MIT
License Family: permissive
Topics: ruby, typechecker
Last push: 2026-08-26T10:06:30+00:00

## Health v2 (maintenance only)
Score: 79/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 99, release rhythm 40, longevity 100
- inputs: {"age_days": 3446, "days_push": 7, "days_rel": 533, "gap_med": 9, "n_releases_24m": 10}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1488, forks 118 (observed 2026-08-28T04:04:52.137551+00:00)

## What it is
Steep is a static type checker for Ruby based on gradual typing, using RBS signature files and inline annotations. It is distributed as a Ruby gem with a CLI and Steepfile configuration.

## Use cases
- statically type check a ruby codebase
- add gradual typing to ruby project with rbs signatures
- catch type errors in ruby before runtime
- verify ruby method signatures against implementations
- set up type checking in ci for ruby

## When to choose
- you want static type checking for Ruby with explicit RBS type declarations
- your team is willing to maintain .rbs signature files
- you want gradual typing where untyped code is skipped rather than rejected

## When to avoid
- you want automatic type inference without writing signatures
- you prefer inline-only typing like Sorbet's RBI/RBS annotations workflow
- your Ruby version is older than 2.6

## Facets
- artifact type: cli-tool
- maturity: active
- function: type-system, linter, cli
- domain: programming-languages, developer-tools, testing
- platform: ruby, cli, cross-platform
- tags: ruby, rbs, static-analysis, gradual-typing, typechecker

## Member repositories
- soutaro/steep (main) score 79

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:04:52.137551+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 2026-08-30T04:33:46.253535+00:00, confidence not recorded.
  - readme: https://github.com/soutaro/steep (fetched 2026-08-28T04:04:52.137551+00:00, sha acd08839ec40)
- Data as of 2026-08-30T08:39:29.467469+00:00.