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

# Introduction

> Getting started with the OpenCharges API is simple.

<Note>
  You must have an enterprise account to have access to the REST API.
</Note>

## Welcome

<Note>
  The OpenCharges API is currently in Beta.
</Note>

<Card title="OpenCharges API Endpoints" icon="rocket" href="https://github.com/open-charges/docs/blob/production/api-reference/openapi.json">
  View the OpenAPI specification file
</Card>

## Authentication

All API endpoints are authenticated using Bearer tokens and picked up from the specification file.

```sh theme={"system"}
curl --request GET \
  --url https://app.opencharges.com/api/v1/{resource} \
  --header 'Authorization: Bearer {token}'
```

## Request Units (RU)

All endpoints have the Request Units (RU) concept. The calculation for utilization is as follows:

* An API request counts as a single RU
* Then, add the number of records returned by the above request

For example, a single GET request for the NPIs endpoint that returns 20 NPIs will count as a total of 21 RUs. 1 for the request itself, and 20 for the number of records returned.

This is to incentivise bulk or chunking of the requests to return as much data as possible in a single request.

## Rate Limits

Rate limits are based on the "Team", not the API Token being used.