Repolode
Submit
crytic

crytic/echidna

Echidna is a Haskell-based fuzzer that tests Ethereum smart contracts by trying call sequences to break user-defined invariants or Solidity assertions.

View on GitHubWebsite
Stars
3,189
Forks
436
Open issues
107
Last commit
24 hours ago

What is it?

Echidna is a fuzzing and property-based testing tool for Ethereum smart contracts. It generates grammar-based call sequences from a contract's ABI and checks user-defined invariants, which are functions prefixed with echidna_ that return a bool, or Solidity assert() statements. When it finds a sequence that falsifies a property, it reports that sequence, and it can minimize the test case for easier triage.

The tool supports several testing modes, including property, assertion, Foundry-style tests, formal-style verification of single transactions, integer overflow detection, optimization of int256 return values, and coverage-only exploration. It works with contracts built by Foundry, Hardhat, and Truffle through crytic-compile, and uses Slither to extract information before fuzzing. Results can be shown in an interactive terminal UI, plain text, or JSON, and a coverage-maximizing corpus can be saved and annotated on the source code.

Key features

  • 01Generates call sequences tailored to a contract's ABI and source code.
  • 02Tests echidna_ prefixed boolean invariants and Solidity assertions.
  • 03Minimizes failing test cases for quicker triage.
  • 04Reports line coverage with source code annotations.
  • 05Supports text, JSON, and interactive terminal output.
  • 06Integrates with Foundry, Hardhat, and Truffle projects via crytic-compile.

Use cases

  • Finding invariant violations in DeFi protocol contracts before deployment.
  • Checking token contracts for balance or overflow bugs.
  • Running smart contract property tests in a GitHub Actions workflow.
  • Reproducing fuzzing research examples on Solidity contracts.

Quick start

  1. 1

    Install Echidna with Homebrew (macOS / Linux)

    brew install echidna
  2. 2

    Run Echidna on the example contract from the README

    echidna tests/solidity/basic/flags.sol

Things to know

  • Vyper support is limited.
  • Some library support for testing is limited.
  • Installing Echidna requires Slither, which is an extra dependency to set up.
  • Container images currently only build on x86 systems.

In collections

Security scanners, audits & threat intel toolsTesting frameworks & test automation tools

Topics

#ethereum#smart-contracts#solidity#fuzzing#security#property-based-testing#haskell#evm#fuzzer#testing

FAQ

What is echidna?
Echidna is a Haskell-based fuzzer that tests Ethereum smart contracts by trying call sequences to break user-defined invariants or Solidity assertions. Echidna is a fuzzing and property-based testing tool for Ethereum smart contracts. It generates grammar-based call sequences from a contract's ABI and checks user-defined invariants, which are functions prefixed with echidna_ that return a bool, or Solidity assert() statements. When it finds a sequence that falsifies a property, it reports that sequence, and it can minimize the test case for easier triage.
Is echidna free to use? What license does it have?
echidna is open source under the AGPL-3.0 license. Check the license terms before using it in commercial products.
Is echidna still maintained?
Actively maintained. The last commit to echidna was on Nov 6, 2026.
What can I use echidna for?
Finding invariant violations in DeFi protocol contracts before deployment. Checking token contracts for balance or overflow bugs. Running smart contract property tests in a GitHub Actions workflow. Reproducing fuzzing research examples on Solidity contracts.
How do I install echidna?
Install Echidna with Homebrew (macOS / Linux): brew install echidna Run Echidna on the example contract from the README: echidna tests/solidity/basic/flags.sol
Where can I get echidna?
The source code and installation instructions are on GitHub: https://github.com/crytic/echidna

Summary generated by AI from the project's README. GitHub stats refresh daily.

Related projects