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

# Get started with the Heymarket API

> An overview of the Heymarket REST API: what it is, what you can build with it, the base URL, JSON encoding requirements, and mandatory HTTPS.

Heymarket is a business messaging platform for SMS, MMS, and email conversations. The Heymarket API gives you programmatic access to customer-facing messaging workflows, including sending messages, managing contacts, organizing lists, and tracking conversations.

Use the API when you need to connect Heymarket to a CRM, ecommerce system, internal tool, data pipeline, or custom customer workflow.

## What you can do

With the Heymarket API you can:

* **Send messages** - send SMS, MMS, and email messages to individual contacts or lists
* **Manage contacts** - create, update, search, delete, and enrich contact records
* **Track conversations** - open, close, reassign, and transfer customer conversations
* **Organize lists** - build and manage contact lists for broadcast messaging
* **Use templates** - create and send saved message templates
* **Schedule messages** - queue messages to send at a specific time
* **Receive webhooks** - subscribe to real-time events for inbound messages and status changes

## Base URL

Send all API requests to:

```text theme={null}
https://api.heymarket.com
```

## JSON encoding

Request bodies must be JSON-encoded. Most object responses are JSON; some endpoints and errors return plain text or string values as shown in the API reference. Set `Content-Type: application/json` on every request that includes a body.

```bash theme={null}
Content-Type: application/json
```

## HTTPS requirement

The Heymarket API accepts requests over HTTPS. Requests made over plain HTTP or without authentication fail.

## Authentication

Every endpoint in the OpenAPI reference requires authentication. API Secret JWT authentication is recommended for new integrations.

See [Authentication](/authentication) for all supported methods.

## Next steps

<CardGroup cols={2}>
  <Card title="Authentication" icon="key" href="/authentication">
    Create an API Secret and learn how to authenticate every request.
  </Card>

  <Card title="Rate limits" icon="gauge" href="/rate-limits">
    Understand rate limits, request IDs, and how to handle errors.
  </Card>

  <Card title="Send a message" icon="message" href="/guides/send-message">
    Follow a step-by-step guide to send your first SMS or MMS.
  </Card>

  <Card title="API reference" icon="code" href="/api-reference/contacts/overview">
    Browse the full reference for all available endpoints.
  </Card>
</CardGroup>