> ## 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.

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  <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" />
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## 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.

## Next steps

<Columns cols={3}>
  <Card title="Authentication" icon="key" href="/api-reference/authentication">
    How to authenticate requests with API keys.
  </Card>

  <Card title="Versioning" icon="code-branch" href="/api-reference/versioning">
    How we version the API.
  </Card>

  <Card title="Rate limiting" icon="gauge" href="/api-reference/rate-limiting">
    How our rate limits work.
  </Card>
</Columns>

<Columns cols={2}>
  <Card title="Error handling" icon="triangle-exclamation" href="/api-reference/error-handling">
    How errors are returned and how to handle them.
  </Card>

  <Card title="Webhooks" icon="share-nodes" href="/api-reference/webhook-object-model">
    How webhook work and their payloads.
  </Card>
</Columns>