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

# Getting Started

> Start sending and receiving WhatsApp messages with the Zapster API. Official (WABA) and unofficial (QR code) connections through a single REST API.

<CardGroup cols={2}>
  <Card title="Send messages" href="/en/v1/guides/send-waba-messages">
    Send your first WhatsApp message using the API.
  </Card>

  <Card title="Set up webhooks" href="/en/v1/concepts/webhooks">
    Receive events in real time and integrate with your systems.
  </Card>
</CardGroup>

## For AI agents

<CardGroup cols={2}>
  <Card title="llms.txt" icon="file-lines" href="/llms.txt">
    An index of the whole documentation in the [llmstxt.org](https://llmstxt.org/) format. Paste it as the initial context in Claude Code, Codex, or OpenClaw and the agent gets oriented without browsing page by page.
  </Card>

  <Card title="Zapster CLI" icon="terminal" href="/en/v1/cli/introduction">
    `npm i -g @zapsterapi/cli` installs a wrapper over the REST API tuned for shells and agents. It ships a copy-paste quickstart so the agent can install and configure itself.
  </Card>
</CardGroup>

## Concepts

<CardGroup cols={2}>
  <Card title="What is an instance?" href="/en/v1/concepts/instances">
    Learn the concepts and terminology behind instances.
  </Card>

  <Card title="What are webhooks?" href="/en/v1/concepts/webhooks">
    Concepts and terminology behind webhooks.
  </Card>

  <Card title="Access tokens" href="/en/v1/concepts/tokens">
    Understand what they are and how they work.
  </Card>

  <Card title="Rate limit" href="/en/v1/concepts/rate-limit">
    The 3 req/s limit, the `RateLimit-*` headers, the 429, and how to handle it.
  </Card>
</CardGroup>