Fuzzing Python Packages

hypothesis

The property-based testing library for Python

schemathesis

Catch API bugs before your users do

crosshair-tool

An analysis tool for Python that blurs the line between testing and type systems.

dnstwist

Domain name permutation engine for detecting homograph phishing attacks, typo squatting, and brand impersonation

advent-of-code

🎄Advent of Code with Rust 🦀

hypothesmith

Hypothesis strategies for generating Python programs, something like CSmith

boofuzz

A fork and successor of the Sulley Fuzzing Framework

ffpuppet

A Python module that enables the automation of Firefox

dirsearch

Web path scanner

prefpicker

Manage & generate prefs.js files

pysource-codegen

generate random python code to test linter/formatter/and other tools

blint

blint is a Binary Linter that checks the security properties and capabilities of your executables. It can also generate a Software Bill-of-Materials (SBOM) for supported binaries.

grizzly-framework

A cross-platform browser fuzzing framework

fandango-fuzzer

FANDANGO is a language-based fuzzer that leverages formal input specifications (grammars) combined with constraints to generate diverse sets of valid inputs for programs under test.

ordeal

Automated chaos testing for Python — fault injection, property assertions, and stateful exploration

hypofuzz

Adaptive fuzzing of Hypothesis tests

clusterfuzz

Scalable fuzzing infrastructure.

kittyfuzzer

Fuzzing framework written in python

corpus-replicator

A corpus generation tool

mcp-assert

The testing standard for MCP servers. Lint (14 rules), test, and fuzz over real stdio/SSE/HTTP transport. 18 assertion types in YAML. Found 4,794 schema issues across 55 servers. Any language, no mocks, single binary.

grammarinator

ANTLR v4 grammar-based test generator

isla-solver

The ISLa (Input Specification Language) language & solver.

katnip

Extension library for the Kitty fuzzing framework

pyradamsa

Python bindings for calling radamsa mutators