# Ethereum Attestation Service (EAS)

> Sign and verify data about anything. Open-source attestation infrastructure for developers and AI agents — no API keys, public good, multi-chain.

## What EAS is

EAS is open infrastructure for making structured data verifiable. You define a schema, sign an attestation against it, and anyone can verify it onchain or offchain. It is built for developers and for machines: AI evals, model runs, and agent actions can be signed by the machine that produced them, so others can rely on the output.

Common uses: machine-signed outputs, authenticity of documents and files, reputation systems, real-world asset verification, private proofs, data oracles, ticketing, voting, proof-of-X, and portable KYC/credentials.

Principles: open source, public good, zero API keys, Ethereum-native, multi-chain (Arbitrum, Base, Celo, Ethereum, Linea, OP Mainnet, Polygon, Scroll, and more).

## Links

- Site: https://attest.org
- GitHub: https://github.com/ethereum-attestation-service
- SDK (TypeScript/JS): https://github.com/ethereum-attestation-service/eas-sdk
- CLI (built for agents): https://github.com/ethereum-attestation-service/eas-cli