Practical overview
When it fits
Use Echidna when example-based tests do not adequately explore stateful contract call sequences and you want fuzzing to search for counterexamples to explicit properties or assertions.
Who it is for
- Solidity smart-contract developers
- Security testers working with Ethereum or EVM contracts
- Teams building automated property-testing or regression-testing workflows
Documented uses
- Fuzz contract call sequences against Solidity invariants.
- Detect assertion failures and integer overflows.
- Run Foundry-style tests and stateful fuzzing campaigns.
- Collect coverage-oriented corpora and minimize failing test cases.
- Integrate testing for contracts built with Foundry, Hardhat or Truffle.
Requirements & limits
The cited evidence identifies Echidna as open source, publicly hosted on GitHub, and distributed under the AGPL-3.0 license. It is documented as a CLI tool.
- Properties must follow the documented echidna_ naming and boolean-return conventions in property mode.
- The tool supports several testing modes, including property, assertion, Foundry, verification, overflow, optimization and exploration.
- Foundry, Hardhat and Truffle compilation workflows are supported through crytic-compile.
- Coverage corpus collection requires the corpusDir configuration option.
- Complex-contract testing can use existing network state or known-ABI contract calls when configured.
Check current requirements in the official documentation. Source-based guidance does not mean OpenViST has run or independently tested this project.
Run a basic Solidity invariant campaign
Check a Solidity contract’s echidna_-prefixed boolean invariants and obtain a counterexample sequence when one is falsified.
Before you start
- A Solidity contract containing zero-argument functions beginning with echidna_ that return bool.
- The Echidna executable.
- A contract source file such as myContract.sol.
Steps
Add an invariant function, such as a balance check, to the contract.
Run echidna myContract.sol.
Review the reported call sequence if Echidna finds a falsifying input.
Expected outcome
Echidna reports a call sequence for a falsified invariant; if it cannot find one, the documented result is that no falsifying input was found during the campaign.
Guide limitations
- Not finding a falsifying input does not establish that the contract is safe.
- The documented command covers the basic property mode and does not describe installation or campaign-duration settings.
Sources & review
Source record details
- Source availability
- Active
- Sources checked
- 1 October 2026
- Original website title
- crytic/echidna · Official homepage title · retained in its source language

