> ## Documentation Index
> Fetch the complete documentation index at: https://docs.quoindata.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Requests and responses

> Base URL, request format and the response envelope.

## Requests

* **Base URL:** `https://portal.quoindata.com/api/v4`
* **Method:** every endpoint is `GET`. Parameters go in the path or query string.
* **Auth:** `Authorization: Bearer <API key>`. See [Authentication](/authentication).
* **Idempotency:** send `Idempotency-Key` on billable calls. See [Idempotency](/api-basics/idempotency).
* **Encoding:** URL-encode query values, especially `q` and `filter`. `curl -G --data-urlencode` does it for you.

Unknown query parameters are rejected with `400 invalid_request`, so typos surface immediately.

## Response envelope

Every response, success or error, has the same shape:

```json theme={null}
{
  "contract_version": "quoin-v4",
  "operation": "records",
  "request_id": "7d3f0c52-1b8e-4c0a-9a43-2f3c7b0f6a11",
  "status": "ok",
  "data": {
    "q_id": "addr_01a12e0d-2ece-77ad-b5b0-430ab9658f29",
    "items": [],
    "next_cursor": "eyJhZnRlciI6InJlY18uLi4ifQ"
  },
  "error": null,
  "meta": {
    "served_at": "2026-10-13T12:00:00.000Z",
    "next_cursor": "eyJhZnRlciI6InJlY18uLi4ifQ"
  }
}
```

| Field | Meaning |
| - | - |
| `contract_version` | Always `quoin-v4` for this API |
| `operation` | The endpoint that ran |
| `request_id` | Your `Idempotency-Key`, or a generated id. Include it when you contact support |
| `status` | `ok` or `error` |
| `data` | The result. `items` holds the rows; single-entity calls also echo `q_id` or `record_ref` |
| `error` | `null` on success; otherwise `code`, `message` and `retryable`. See [Errors](/api-basics/errors) |
| `meta.next_cursor` | Present when more results exist. See [Pagination](/api-basics/pagination) |

Responses are capped at 256 KiB. Larger results return `422 response_too_large`; lower `limit`.

## Response headers

| Header | Meaning |
| - | - |
| `X-Quoin-Charged-Micro-USD` | Amount charged for this call, in millionths of a dollar. `0` for free calls and replays |
| `X-Quoin-Balance-Micro-USD` | Remaining account credit, in millionths of a dollar |
| `X-Quoin-Replayed` | `true` when this is a stored replay of an earlier call with the same `Idempotency-Key` |
| `X-RateLimit-Limit`, `X-RateLimit-Remaining`, `X-RateLimit-Reset` | Per-minute rate limit state. See [Rate limits](/api-basics/rate-limits) |
| `X-Quoin-API-Version` | `quoin-v4` |


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