# Dropnation/contract-fuzzer

Ethereum smart contract fuzzer

Repository: https://github.com/Dropnation/contract-fuzzer
Canonical: https://ross.abutalabs.com/products/contract-fuzzer
Homepage: https://developers.stellar.org/docs/build/smart-contracts/example-contracts/fuzzing
Language: Python
License: MIT
License Family: permissive
Topics: ethereum, evm, fuzzer, fuzzing, smart-contract, testing
Last push: 2026-08-21T07:19:24+00:00

## Health v2 (maintenance only)
Score: 71/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 98, release rhythm 64, longevity 21
- inputs: {"age_days": 305, "days_push": 12, "days_rel": 29, "gap_med": 276, "n_releases_24m": 2}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1414, forks 169 (observed 2026-08-28T04:04:39.603651+00:00)

## What it is
A Python-based fuzzer for Ethereum smart contracts that compiles Solidity sources and executes random sequences of public/external calls to verify user-defined `echidna_*` property functions. It runs locally using an in-process EVM (eth-tester + py-evm) and supports reproducible runs via seeds with saved failure artifacts.

## Use cases
- fuzz test solidity smart contracts for property violations
- find bugs in ethereum contracts before deployment
- replay a failing contract fuzz run
- run echidna-style property tests on evm contracts
- fuzz solidity contracts on windows without docker
- generate reproducible smart contract test failures with seeds

## When to choose
- you want a lightweight, pip-installable EVM contract fuzzer with no external binaries
- you need reproducible fuzzing runs with saved failure artifacts
- you already write echidna_* style property functions in Solidity

## When to avoid
- you need coverage-guided scheduling or parallel fuzzing workers, which are still on the roadmap
- you need advanced input shrinking/minimization of failing sequences
- you fuzz Soroban/Stellar or non-EVM smart contracts

## Facets
- artifact type: cli-tool
- maturity: active
- function: fuzzing, testing, cli
- domain: security, blockchain, testing, developer-tools
- platform: python, cli, cross-platform, windows
- tags: ethereum, evm, solidity, smart-contract-security, property-testing, echidna-style, py-evm, reproducible-fuzzing, linux, macos, docker

## Member repositories
- Dropnation/contract-fuzzer (main) score 71

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:04:39.603651+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 2026-08-30T04:38:11.098513+00:00, confidence not recorded.
  - readme: https://github.com/Dropnation/contract-fuzzer (fetched 2026-08-28T04:04:39.603651+00:00, sha f9763c60cae5)
  - homepage: https://developers.stellar.org/docs/build/smart-contracts/example-contracts/fuzzing (fetched 2026-08-29T11:51:15.002391+00:00, sha e07620d55105)
  - site_page: https://developers.stellar.org/docs/build/building-with-ai (fetched 2026-08-29T11:51:15.007666+00:00, sha 4444918b09a0)
  - site_page: https://developers.stellar.org/docs/build (fetched 2026-08-29T11:51:15.005931+00:00, sha e27447cf8fa3)
  - site_page: https://developers.stellar.org/docs/build/smart-contracts (fetched 2026-08-29T11:51:15.009259+00:00, sha 1ef82c3f4ac7)
  - site_page: https://developers.stellar.org/docs/build/smart-contracts/overview (fetched 2026-08-29T11:51:15.010837+00:00, sha 9555f1dafeb8)
  - site_page: https://developers.stellar.org/docs/build/smart-contracts/getting-started (fetched 2026-08-29T11:51:15.012729+00:00, sha 7c94869a764c)
  - site_page: https://developers.stellar.org/docs/build/smart-contracts/example-contracts (fetched 2026-08-29T11:51:15.014276+00:00, sha 5362883fcc75)
  - site_page: https://developers.stellar.org/docs/build/apps (fetched 2026-08-29T11:51:15.015982+00:00, sha ea6151846462)
  - site_page: https://developers.stellar.org/docs/build/apps/overview (fetched 2026-08-29T11:51:15.017692+00:00, sha 62933d1ef73d)
- Data as of 2026-08-30T08:39:29.467469+00:00.