---
title: Introduction
description: "Fundamental concepts of Usend's API."
---

## Base URL

Unsend's API is built on REST principles and is served over HTTPS. To ensure data privacy, unencrypted HTTP is not supported.

The Base URL for all API endpoints is:

```sh Terminal
https://app.unsend.dev/api/
```

## Authentication

Authentication to Usend's API is performed via the Authorization header with a Bearer token. To authenticate, you need to include the Authorization header with the word Bearer followed by your token in your API requests like so:

```sh Terminal
Authorization: Bearer us_12345
```

You can create a new token/API key under your Unsend [Developer Settings](https://app.unsend.dev/api-keys).
