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

# API Overview

> Learn how to authenticate and interact with the Open Pay REST API

## Base URL

All API requests should be made to:

```
https://olp-api.nipuntheekshana.com
```

## Versioning

The API is versioned via URL path prefix. The current version is **v1**.

```
https://olp-api.nipuntheekshana.com/v1/{resource}
```

## Content Type

All requests and responses use JSON. Set the following header on every request:

```
Content-Type: application/json
```

## Authentication

Most endpoints require a Bearer token obtained via the [Login](/api-reference/auth/login) or [Register](/api-reference/auth/register) endpoints.

Include the token in the `Authorization` header:

```
Authorization: Bearer <your_token>
```

For server-to-server integrations, you can authenticate using API keys created through the [Manage API Keys](/api-reference/merchants/manage-api-keys) endpoint. Pass the API key in the `X-API-Key` header:

```
X-API-Key: <your_api_key>
X-API-Secret: <your_api_secret>
```

## Rate Limits

API requests are rate-limited to protect the platform from abuse.

| Tier     | Limit        | Window   |
| -------- | ------------ | -------- |
| Default  | 100 requests | 1 minute |
| Auth     | 20 requests  | 1 minute |
| Checkout | 50 requests  | 1 minute |

When you exceed a rate limit, the API returns a `429 Too Many Requests` response with the following headers:

| Header                  | Description                              |
| ----------------------- | ---------------------------------------- |
| `X-RateLimit-Limit`     | Maximum requests allowed in the window   |
| `X-RateLimit-Remaining` | Requests remaining in the current window |
| `X-RateLimit-Reset`     | Unix timestamp when the window resets    |

## Error Format

All errors follow a consistent structure:

```json theme={null}
{
  "error": {
    "code": "VALIDATION_ERROR",
    "message": "email is required",
    "details": {}
  }
}
```

### Common Error Codes

| HTTP Status | Code               | Description                        |
| ----------- | ------------------ | ---------------------------------- |
| 400         | `VALIDATION_ERROR` | Request body or params are invalid |
| 401         | `UNAUTHORIZED`     | Missing or expired token           |
| 403         | `FORBIDDEN`        | Insufficient permissions           |
| 404         | `NOT_FOUND`        | Resource does not exist            |
| 409         | `CONFLICT`         | Resource already exists            |
| 429         | `RATE_LIMITED`     | Too many requests                  |
| 500         | `INTERNAL_ERROR`   | Unexpected server error            |

## Pagination

List endpoints support cursor-based pagination with the following query parameters:

| Parameter | Type    | Default | Description              |
| --------- | ------- | ------- | ------------------------ |
| `page`    | integer | 1       | Page number              |
| `limit`   | integer | 20      | Items per page (max 100) |

Paginated responses include:

```json theme={null}
{
  "data": [],
  "pagination": {
    "page": 1,
    "limit": 20,
    "total": 85,
    "totalPages": 5
  }
}
```