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

# BRP API: Introduction

> API for Balancing Responsible Parties to manage contracts, transactions, nominations, and customers

The Otark BRP API provides programmatic access to the BRP Portal, enabling Balancing Responsible Parties to manage contracts, view transactions and nominations, and handle customer assignments.

<h3 id="base-url">
  Base URL
</h3>

```
https://api.otark.energy/v1
```

All requests must use HTTPS. Responses are returned in JSON format.

<h3 id="authentication">
  Authentication
</h3>

All requests must include the `X-Api-Key` header:

```bash theme={null}
curl -X GET "https://api.otark.energy/v1/contracts" \
-H "X-Api-Key: YOUR_API_KEY"
```

API keys can be generated in the BRP Portal. Store your key securely — it grants full access to your BRP account.

<h3 id="data-model">
  Data Model
</h3>

The API is organized around three core resources that form a hierarchy:

```
Contract (PPA, etc.)
 └── Transaction (contractual energy volumes between buyer and seller)
       └── Nomination (net saldo, aggregated by balance group)
```

* **Contracts** represent energy agreements (e.g., PPAs) between a seller and a buyer. Contracts are polymorphic — the schema varies by type.

* **Transactions** represent the contractual energy volumes to be transferred between buyer and seller under a contract. Transactions are immutable; corrections produce a new version that supersedes the previous one.

* **Nominations** are the net saldo of valid transactions, aggregated by balance group and delivery period. Nominations are also versioned.

* **Customers** represent energy consumers or producers assigned to a BRP. Two customers make up either party of a contract. Customers can be approved, rejected, and configured with balance group settings.

<h3 id="getting-started">
  Getting Started
</h3>

1. **Obtain an API key** from the BRP Portal.
2. **Explore your contracts and customers** by calling `GET /v1/contracts` and `GET /v1/customers`.
3. **View transactions** for a contract using `GET /v1/contracts/{contract_id}/transactions`.
4. **Check nominations** with `GET /v1/nominations`.

<Note>
  See [API Conventions](/brp/api-conventions) for details on pagination, error handling, timestamps, and rate limiting.
</Note>

<h3 id="support">
  Support
</h3>

If you have any questions or need further assistance, contact us at [support@otark.com](mailto:support@otark.com).