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

# REST API

> Learn how to use SuprSend REST APIs to sync users and send notifications at scale.

The **SuprSend REST API** enables you to sync user data and send notifications at scale.

We have [SDKs](/docs/developer/sdk-overview) for most popular languages. If your backend or frontend is built in another language or you prefer direct integration, you can use the REST API to programmatically interact with SuprSend.

***

## Authentication

REST APIs require an **API Key** for authentication. API Keys are scoped **per workspace** (e.g., Sandbox, Staging, Production), ensuring isolation across environments.

Include your API Key in the `Authorization` header as a `Bearer` token:

```http theme={"system"}
Authorization: Bearer <YOUR_API_KEY>
Content-Type: application/json
```

## API Reference

For a complete list of endpoints and request/response schemas, see the [API Reference](/reference/overview).

## Postman Collection

The fastest way to get started is by exploring the APIs in our [Postman Collection](https://www.postman.com/suprsend/workspace/suprsend/collection/27786422-d77a13c1-8f59-406d-9669-078a10d52521).