# google/atheris

Repository: https://github.com/google/atheris
Canonical: https://ross.abutalabs.com/products/atheris
Language: Python
License: Apache-2.0
License Family: permissive
Last push: 2026-06-17T17:35:18+00:00

## Health v2 (maintenance only)
Score: 72/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 88, release rhythm 35, longevity 100
- inputs: {"age_days": 2116, "days_push": 77, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1664, forks 126 (observed 2026-08-28T04:05:18.938326+00:00)

## What it is
Atheris is a coverage-guided fuzzing engine for Python code and native CPython extensions, built on top of libFuzzer. It instruments Python bytecode to collect coverage and can combine with AddressSanitizer or UndefinedBehaviorSanitizer to find bugs in native code.

## Use cases
- fuzz a python parsing library for crashes
- find uncaught exceptions in python code with random inputs
- fuzz native C extension modules for memory bugs
- coverage-guided fuzz testing of python packages
- detect undefined behavior in python native extensions

## When to choose
- you want automated coverage-guided fuzzing of Python code or CPython extensions
- you need libFuzzer-style fuzzing integrated with Python
- you want to catch memory bugs in native extensions with sanitizers

## When to avoid
- you need fuzzing on Windows or Python <= 3.10
- you want property-based testing with structured generators rather than raw byte fuzzing
- you need to fuzz non-Python codebases

## Facets
- artifact type: library
- maturity: active
- function: fuzzing, testing
- domain: testing, security, developer-tools
- platform: python, cli
- tags: coverage-guided-fuzzing, libfuzzer, sanitizers, native-extensions, linux, macos

## Member repositories
- google/atheris (main) score 72

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:18.938326+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 2026-08-30T03:44:28.834384+00:00, confidence not recorded.
  - readme: https://github.com/google/atheris (fetched 2026-08-28T04:05:18.938326+00:00, sha 86e936c5a142)
  - registry_pypi: https://pypi.org/pypi/atheris/json (fetched 2026-08-29T11:16:37.571435+00:00, sha 2758be764077)
- Data as of 2026-08-30T08:39:29.467469+00:00.