API Overview - OpenContract

Base URL

https://api.opencontract.io/v1

Authentication

See Authentication for how to get a key by signing a server-issued nonce — there’s no dashboard or sign-up form. Once you have one, include it as a bearer token in every request:

curl https://api.opencontract.io/v1/contracts \
  -H "Authorization: Bearer <YOUR_API_KEY>"

Request Format

All request bodies must be JSON. Set the Content-Type header accordingly:

Content-Type: application/json

Response Format

All responses return JSON with a consistent envelope:

{
  "data": { ... },
  "meta": {
    "requestId": "req_abc123",
    "timestamp": "2026-06-02T00:00:00Z"
  }
}

Error Codes

Status	Code	Description
400	`invalid_request`	Missing or malformed parameters
401	`unauthorized`	Invalid or missing API key
404	`not_found`	Resource does not exist
409	`conflict`	Bid too low or auction already ended
429	`rate_limited`	Too many requests
500	`internal_error`	Server-side error

Error responses follow this shape:

{
  "error": {
    "code": "invalid_request",
    "message": "reservePrice must be a positive number"
  }
}

Rate Limits

Plan	Requests / minute
Free	60
Pro	600
Enterprise	Unlimited