Verifying quote signatures

Every quote from POST /v1/quotes carries a top-level signature: an EIP-712 signature by the address published as quoteSigner on the source chain’s entry in GET /v1/chains. Verification is one hash and one signature recovery, with no API key and no extra call. With options.allQuotes, each entry in quotes carries its own signature.

What is signed

domain:  { name: "EcoQuoteV1", version: "1", chainId: <source.chainId> }
Quote(string id, bytes32[] intentHashes, uint64 expiresAt)

Field	Taken from
`id`	`quote.id`, including the `quote:` prefix
`intentHashes`	`quote.intentHash` plus every `steps[].intents[].intentHash`: lowercased, de-duplicated, sorted ascending as strings
`expiresAt`	`quote.expiresAt`, Unix seconds
domain `chainId`	`quote.source.chainId`

An intent hash already commits to the route, reward, recipient, and amounts, so changing any of them changes the hash and breaks the signature. The funding calldata is intentionally outside the signature. The source chain lives in the domain, so a signature for a Base quote does not verify as an OP Mainnet quote.

Verify

import { hashTypedData, recoverAddress } from 'viem';

const intentHashes = [quote.intentHash, ...quote.steps.flatMap((s) => s.intents.map((i) => i.intentHash))]
  .filter(Boolean)
  .map((h) => h.toLowerCase());

const digest = hashTypedData({
  domain: { name: 'EcoQuoteV1', version: '1', chainId: quote.source.chainId },
  types: {
    Quote: [
      { name: 'id', type: 'string' },
      { name: 'intentHashes', type: 'bytes32[]' },
      { name: 'expiresAt', type: 'uint64' },
    ],
  },
  primaryType: 'Quote',
  message: {
    id: quote.id,
    intentHashes: [...new Set(intentHashes)].sort(),
    expiresAt: BigInt(quote.expiresAt),
  },
});

const signer = await recoverAddress({ hash: digest, signature: quote.signature });
// Compare case-insensitively with chains[source.chainId].quoteSigner from GET /v1/chains.

The same recovery applies whether the source chain is EVM or Solana; only the domain chainId differs.

What a match proves

A matching signer proves the quote was issued by Eco, names exactly those intents, and has not been altered or extended past expiresAt. It does not prove the price is the best available, and it does not cover the bytes of execution.transaction. Read quoteSigner from GET /v1/chains and cache it with a refresh rather than pinning it in code. The published signer can rotate.

Conventions

Discovery and quotes

Quote funding and status

Circle Gateway fast deposits

Open quoting service

Verifying quote signatures

What is signed

Verify

What a match proves

​What is signed

​Verify

​What a match proves

What is signed

Verify

What a match proves