API reference

POST /v1/onchain_verifications

Exchanges a SIWE signature for a signed verification. No API key — the SIWE signature is the credential, and the verification is only usable by the signing wallet at the contract it names.

Request

{
  "message": "<SIWE message; its Resources line names your contract>",
  "signature": "0x<wallet signature over the message>"
}

Response `200`

{
  "identityHash": "0x<bytes32>",
  "expiration": 1723497600,
  "signature": "0x<eip-712 signature>"
}

Pass these straight to your contract's claim function.

Errors

Status	Meaning
`400`	Malformed or expired SIWE, wrong statement, or wrong chain
`404` contract_not_found	The named contract isn't deployed or doesn't expose a policy
`404` verification_not_found	The wallet has no credential for the contract's provider
`404` needs_reauth	The credential predates the contract's `cutoffBlock` — send the user to re-verify
`400` conditions_not_satisfied	The credential doesn't meet the contract's conditions
`400` invalid_policy	The contract's provider/condition/operator combo isn't supported

SIWE requirements

statement must be exactly: Claim eligibility for a Base Verify onchain benefit.
Resources must include eip155:<chainId>:<yourContractAddress>.
chainId must be the chain you're claiming on — Base Sepolia (84532) during the test phase.

API reference

POST /v1/onchain_verifications

Request

Response 200

Errors

SIWE requirements

Response `200`