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

# Welcome

> Courier is infrastructure for product-to-user communication. Send notifications across email, SMS, push, chat, and in-app channels through one API.

## Start Here

<CardGroup cols={3}>
  <Card title="What is Courier?" icon="circle-info" href="/getting-started/introduction">
    Why teams use Courier and what the platform covers: routing, templates, inbox, preferences, and more.
  </Card>

  <Card title="Send your first notification" icon="bolt" href="/getting-started/quickstart">
    Follow the developer quickstart to make your first API call in a few minutes.
  </Card>

  <Card title="Building with AI?" icon="microchip-ai" href="/tools/agent-quickstart">
    Start with the agent quickstart for copy-paste patterns, guardrails, and API workflows.
  </Card>
</CardGroup>

## Resources

* [API Reference](/reference/get-started) — REST API docs for sending, users, preferences, automations, and more.
* [SDKs](/sdk-libraries/sdks-overview) — server and client libraries for Node, Python, Go, Ruby, React, iOS, and Android.
* [Help Center](/help) — contact support, check platform status, and view the changelog.