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Echidna

Property-based fuzzer for Ethereum smart contracts

Trail of Bits' fuzzer that generates transaction sequences to break user-defined invariants and assertions in Solidity contracts.

Open sourceAGPL-3.0-only
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Homepage of Echidna
Official repository page, captured by ThreatWire.

What Echidna does

Echidna takes properties written as Solidity functions or assertions and generates random but grammar-aware sequences of transactions to falsify them. When it finds a failing sequence it shrinks it to a minimal reproduction.

It supports coverage-guided campaigns, corpus collection and on-chain state forking, and is widely used to test invariants in DeFi protocols.

Key features

  • Invariant and assertion testing
  • Coverage-guided transaction generation
  • Automatic shrinking of failing sequences
  • Corpus and coverage reports
  • Foundry, Hardhat and other framework support

Licence

AGPL-3.0-only · GNU AGPL v3 · Open source

Checked by ThreatWire against the repository's licence file on 2026-10-20. GitHub detects: AGPL-3.0.

Security of Echidna itself

No published advisory found for Echidna in GitHub repository advisories. That does not mean the tool has no vulnerabilities.

Sources: GitHub repository advisories · checked 2026-10-20.

Categories and tags

Smart contract securityFuzzing#fuzzing#property-testing#solidity#haskell#evm#ethereum#smart-contracts#security#testing

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