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

# API Reference

> Reference documentation for the Nexio REST API.

REST API over HTTPS. All requests and responses use JSON.

## Base URL

```
https://api.usenexio.com
```

Versioned REST endpoints live under `/api/v1/`. The unauthenticated health check is `GET /health`.

## Authentication

Bearer token required on all `/api/v1/*` endpoints. `GET /health` does not require authentication. See [Authentication](/api-reference/authentication).

## Error format

All errors use a standard envelope:

```json theme={null}
{
  "code": "invalid_request",
  "message": "Request body is not valid JSON"
}
```

`code` is stable and safe to match programmatically. `message` is human-readable and may change.

## Status codes

| Code  | Meaning                                                                        |
| ----- | ------------------------------------------------------------------------------ |
| `200` | Success (GET, PATCH)                                                           |
| `201` | Created (POST webhook)                                                         |
| `202` | Accepted and queued (POST run)                                                 |
| `204` | Deleted (DELETE webhook)                                                       |
| `400` | Malformed request or validation failure                                        |
| `401` | Missing or invalid API key                                                     |
| `404` | Resource not found                                                             |
| `429` | Rate limited: honor `Retry-After` header                                       |
| `503` | Temporary dependency outage, for example auth unavailable or queue unreachable |

## Rate limiting

Per-organization, per-minute window. `429` responses include a `Retry-After` header.

## Versioning

Versions are in the URL path (`/api/v1/`). Breaking changes ship under a new version. Additive
fields may be added to existing versions without notice.

## Health check

```
GET /health → {"status":"ok"}
```

No authentication required.