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

# REST API

## Protocols

The Flinks API is a RESTful service that adheres to HTTP methodologies as defined by [RFC 2616](https://tools.ietf.org/html/rfc2616). It enables secure, structured communication between your application and Flinks services.

### **Protocols & Security**

* **Protocol** : REST over HTTPS

* **Security** : Only TLS v1.2+ is supported. Connections using older versions of TLS will be rejected.

* **Content-Type** : All requests must include the header `application/json`

* **Request Body** : Must be valid JSON when applicable.

## **Environment & URL Structure**

<Note>
  <p class="h4">Note on the API call URL</p>

  In this guide, the sandbox instance is used. Therefore, you will need to adjust the API call URL for your needs.
</Note>

When integrating with Flinks, ensure you use the correct environment (e.g., sandbox or production). The API URL structure includes your instance name and customerId, which are provided during onboarding.

```http http theme={null}
https://{instance}-api.private.fin.ag/v3/{customerId}/BankingServices/Authorize
```

Example:

If your instance is `yourcompany` and your `customerId` is `334a74ab-6592-4431-a6a0-3f5585d8019d`, the URL would be:

```http http theme={null}
https://yourcompany-api.private.fin.ag/v3/334a74ab-6592-4431-a6a0-3f5585d8019d/BankingServices/Authorize
```

## Testing the API

You can test API calls directly from the documentation interface. To do so, you’ll need a valid `loginId` from your production instance.

* Always specify your environment (sandbox or production) in API calls.

* Ensure your customerId and instance are correctly configured.

* Use HTTPS and TLS v1.2+ for all communications.

* Validate your JSON payloads before sending requests.