# crytic/echidna

Ethereum smart contract fuzzer

Repository: https://github.com/crytic/echidna
Canonical: https://ross.abutalabs.com/products/echidna
Homepage: https://secure-contracts.com/program-analysis/echidna/index.html
Language: Haskell
License: AGPL-3.0
License Family: copyleft
Topics: evm, ethereum, smart-contracts, security, solidity, testing, fuzzer
Last push: 2026-08-26T21:34:24+00:00

## Health v2 (maintenance only)
Score: 89/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 71, longevity 100
- inputs: {"age_days": 3293, "days_push": 7, "days_rel": 37, "gap_med": 103.0, "n_releases_24m": 7}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3170, forks 432 (observed 2026-08-28T04:07:47.436817+00:00)

## What it is
Echidna is a Haskell-based fuzzer for Ethereum smart contracts that performs property-based testing by generating sequences of contract calls to falsify user-defined invariants or Solidity assertions. It uses grammar-based fuzzing with coverage guidance, corpus collection, and Slither integration to find deep bugs in EVM contracts.

## Use cases
- fuzz my solidity smart contract for bugs
- test that a contract invariant always holds
- find call sequences that break my token's balance guarantees
- property-based testing for ethereum contracts
- check solidity assertions with random inputs
- audit smart contracts before deployment
- verify my defi protocol's security invariants

## When to choose
- you need to test Solidity invariants or assertions against randomized call sequences
- you want coverage-guided fuzzing with corpus collection and test case minimization
- you are auditing or hardening Ethereum smart contracts before deployment
- you prefer a mature, widely adopted tool with extensive documentation and tutorials

## When to avoid
- you need parallelized fuzzing or a Go API for custom testing methodology (consider medusa)
- your project is not EVM/Solidity based
- you need formal verification with mathematical proofs rather than fuzzing
- you want symbolic execution rather than input generation

## Facets
- artifact type: cli-tool
- maturity: active
- function: testing, fuzzing, security, vulnerability-scanning
- domain: security, blockchain, developer-tools, testing
- platform: cli
- tags: ethereum, solidity, evm, property-based-testing, smart-contract-security, invariant-testing, haskell, smart-contracts, linux, macos, docker

## Member repositories
- crytic/echidna (main) score 89

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:07:47.436817+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 2026-08-29T18:45:29.422268+00:00, confidence not recorded.
  - readme: https://github.com/crytic/echidna (fetched 2026-08-28T04:07:47.436817+00:00, sha 42b6790fd2c9)
  - homepage: https://secure-contracts.com/program-analysis/echidna/index.html (fetched 2026-08-29T09:39:41.989685+00:00, sha 503ea68725a5)
  - site_page: https://secure-contracts.com/program-analysis/echidna/introduction/installation.html (fetched 2026-08-29T09:39:41.991989+00:00, sha 02d7c33bcccc)
  - site_page: https://secure-contracts.com/program-analysis/medusa/docs/src/index.html (fetched 2026-08-29T09:39:41.993612+00:00, sha 6cf1b177e2c0)
  - site_page: https://secure-contracts.com/program-analysis/medusa/docs/src/getting_started/installation.html (fetched 2026-08-29T09:39:41.995104+00:00, sha 10869aaed0a9)
  - site_page: https://secure-contracts.com/program-analysis/medusa/docs/src/getting_started/first_steps.html (fetched 2026-08-29T09:39:41.996815+00:00, sha 8683a44f8cb3)
  - site_page: https://secure-contracts.com/program-analysis/medusa/docs/src/project_configuration/overview.html (fetched 2026-08-29T09:39:41.998205+00:00, sha 110ebc589df4)
  - site_page: https://secure-contracts.com/program-analysis/medusa/docs/src/project_configuration/fuzzing_config.html (fetched 2026-08-29T09:39:41.999692+00:00, sha 0393d2c5bce5)
  - site_page: https://secure-contracts.com/program-analysis/medusa/docs/src/project_configuration/testing_config.html (fetched 2026-08-29T09:39:42.001536+00:00, sha a5e486ece593)
  - site_page: https://secure-contracts.com/program-analysis/medusa/docs/src/project_configuration/chain_config.html (fetched 2026-08-29T09:39:42.003386+00:00, sha 6aeab6d534ea)
- Data as of 2026-08-30T08:39:29.467469+00:00.