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

# Overview

> Welcome to the Heyy Developer Guide! Whether you’re integration a simple API or building complex integrations, this guide will help you implement our API.

<Warning>
  **API v2 is deprecated** and will be sunset on **November 1, 2026**. Use [API v3](/api-reference/v3/overview) for all new integrations.
</Warning>

<Frame>
  <img className="block dark:hidden" src="https://mintcdn.com/heyy-c8bd5c9e/5Pui2IpXex8QDwOQ/assets/banner-light.svg?fit=max&auto=format&n=5Pui2IpXex8QDwOQ&q=85&s=2c9785dc5a06d6116af95e926601031c" alt="Heyy banner" width="1000" height="180" data-path="assets/banner-light.svg" />

  <img className="hidden dark:block" src="https://mintcdn.com/heyy-c8bd5c9e/5-t-_6arANyhmBEc/assets/banner-dark.svg?fit=max&auto=format&n=5-t-_6arANyhmBEc&q=85&s=db33cf2e0b1405d62aaaab3660d4d559" alt="Heyy banner" width="1000" height="180" data-path="assets/banner-dark.svg" />
</Frame>

## Welcome to the Heyy API

The Heyy API is a REST API that lets you build rich messaging experiences on top of Heyy. Use it to:

* Send and receive messages across your connected channels.
* Manage contacts, chats, broadcasts, and more.
* Automate repetitive workflows and integrate Heyy with your existing tools.

Whether you are adding a simple integration or building a full customer messaging platform, this documentation will help you get started quickly and stay productive.