> ## 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.

# Messages

> Understand Heymarket message types, send targets, media, templates, broadcasts, scheduled sends, and private comments.

Messages are the individual units of communication in Heymarket. A message can be an outbound SMS, MMS, email, broadcast, scheduled send, inbound reply, or private internal comment.

Every message belongs to a conversation. Outbound messages are sent from an inbox and attributed to a sender member.

## Send targets

The message send endpoint supports several target patterns. Choose the target that matches your workflow.

| Target         | Use when                                            |
| -------------- | --------------------------------------------------- |
| `phone_number` | Sending an individual SMS or MMS to a phone number. |
| `chat_id`      | Replying inside an existing conversation.           |
| `list_id`      | Broadcasting to a contact list.                     |
| `targets`      | Sending group MMS to multiple phone numbers.        |

Email uses a separate endpoint: `POST /v1/email/send`. For a new email conversation, provide email `targets` with `to:` or `cc:` prefixes. To reply in an existing email conversation, provide `convo_id`.

## Message content

Message content can come from:

* `text` for a direct message body.
* `template_id` for a saved template.
* `media_url` for a public media attachment.

Use `private: true` only as a behavior flag for an internal comment visible to your team.

When sending to a list, include a unique `local_id` so the send can be tracked consistently. A `local_id` is also useful for retry-sensitive sends and webhook reconciliation when your integration needs its own stable identifier.

## SMS, MMS, and email

Use `POST /v1/message/send` for SMS, MMS, broadcasts, and private comments. Use `POST /v1/email/send` for email messages.

MMS requires a publicly accessible `media_url`. Carrier limits can affect supported file size and delivery behavior.

## Scheduled messages

Scheduled messages are queued for a future send time. Use scheduled sends when a workflow needs delayed delivery or campaign timing.

Scheduled messages can be retrieved, updated, or deleted before they are sent.

## Related pages

<CardGroup cols={2}>
  <Card title="Send a message" icon="message" href="/guides/send-message">
    Follow the first-message workflow.
  </Card>

  <Card title="Messages reference" icon="code" href="/api-reference/messages/send">
    Review message send fields and examples.
  </Card>

  <Card title="Email send reference" icon="message" href="/api-reference/messages/send-email">
    Review email-specific target fields.
  </Card>
</CardGroup>