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

# Authentication

> How to authenticate with the Noxpay API.

## Base URL

```
https://checkout.noxpay.io
```

## Authentication

All API requests must include your API key in the `api-key` header:

```http theme={null}
api-key: <key>
```

Your API key is available in the Noxpay dashboard under **Settings → API Keys**.

<Warning>
  Never expose your API key in client-side code. All requests to the Noxpay API must originate from your backend.
</Warning>

## Error responses

All endpoints return JSON error bodies:

```json theme={null}
{ "error": "Unauthorized" }
{ "error": "Bad Request", "details": "currency is required" }
{ "error": "internal error" }
```

| HTTP Status | Meaning                                               |
| ----------- | ----------------------------------------------------- |
| `400`       | Invalid request body or missing required field        |
| `401`       | Missing or invalid API key                            |
| `403`       | Authenticated but insufficient permissions            |
| `404`       | Resource not found or does not belong to your account |
| `500`       | Internal server error                                 |