> ## Documentation Index
> Fetch the complete documentation index at: https://dev.docs.1to1ai.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Messages

> Send text, media, quick replies, and templates with the send_message action, based on the 24h window.

Every WhatsApp send goes through a single action, **`send_message`**, inside the
`POST /conversation/actions` endpoint. One action covers all four modes —text,
media, quick reply, and template—; which one you can use depends on the state of
the conversation's [24h window](/en/conversations).

## Which mode applies based on the window

| Mode         | Window open | Window closed          |
| ------------ | ----------- | ---------------------- |
| Text         | ✅           | ❌ `WINDOW_CLOSED`      |
| Media        | ✅           | ❌ `WINDOW_CLOSED`      |
| Quick reply  | ✅           | ❌ `WINDOW_CLOSED`      |
| **Template** | ✅           | ✅ — reopens the window |

<Tip>
  The **template** is the only message you can send with the window closed. On top
  of that, sending one reopens the window, enabling text, media, and quick reply
  again.
</Tip>

## The four modes of `send_message`

Each `send_message` sends **one kind of content**: text (`body`), media
(`file_uuid`), a quick reply (`quick_reply`), or a template (`template`). The
first three can also carry a fallback template for when the window is closed
(see below).

<Tabs>
  <Tab title="Text">
    Free-form text, up to 4096 characters.

    ```jsonc theme={null}
    {
      "type": "send_message",
      "body": "Hi 👋, how can I help you?"
    }
    ```
  </Tab>

  <Tab title="Media">
    Image, video, audio, or document: pass a `file_uuid` from a file already
    uploaded and confirmed, with `body` as an optional caption. The type is
    inferred from the file; audio does not allow a caption. The upload flow is in
    [Upload media](/en/action-groups/upload-media).

    ```jsonc theme={null}
    {
      "type": "send_message",
      "file_uuid": "7b8a1c2d-3e4f-5678-90ab-cdef12345678",
      "body": "Here is your receipt 📄"
    }
    ```
  </Tab>

  <Tab title="Quick reply">
    A reply preconfigured in the dashboard, identified by `name`
    (case-insensitive). It can emit several messages.

    ```jsonc theme={null}
    {
      "type": "send_message",
      "quick_reply": { "name": "Welcome" }
    }
    ```
  </Tab>

  <Tab title="Template">
    A template approved by Meta — the only mode that works with the window closed.
    `language` is required (Meta format `lower_UPPER`, e.g. `en_US`). See
    [Templates](/en/templates).

    ```jsonc theme={null}
    {
      "type": "send_message",
      "template": {
        "name": "appointment_confirmation",
        "language": "en_US",
        "body_variables": [{ "index": 1, "value": "Ana" }]
      }
    }
    ```
  </Tab>
</Tabs>

## Sending

Sending is an action within the group. Make a `POST /conversation/actions` with a
`send_message` in the `actions` array:

```bash theme={null}
curl -X POST "https://app.1to1.ai/api/v1/public/{slug}/conversation/actions" \
  -H "Authorization: Bearer sk_1to1_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
    "conversation": {
      "phone": "+5215512345678",
      "channel": "ch_7A9K2M4Q"
    },
    "actions": [
      {
        "type": "send_message",
        "body": "Hi 👋, how can I help you?"
      }
    ]
  }'
```

Responds `202`: the send runs in the background. Check the result in the
conversation status or the activity log. To chain several sends or other actions
in a single request, see [Actions](/en/action-groups/overview).

## Template fallback for a closed window

A `send_message` of text, media, or quick reply can also include an optional
`template`: if the window is **closed** when it runs, the template is sent instead
of the primary; if it's **open**, the primary is sent. Without a `template`, a
primary with the window closed fails with `WINDOW_CLOSED`.

```bash theme={null}
curl -X POST "https://app.1to1.ai/api/v1/public/{slug}/conversation/actions" \
  -H "Authorization: Bearer sk_1to1_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
    "conversation": {
      "phone": "+5215512345678",
      "channel": "ch_7A9K2M4Q"
    },
    "actions": [
      {
        "type": "send_message",
        "body": "Hi 👋",
        "template": {
          "name": "reminder",
          "language": "en_US"
        }
      }
    ]
  }'
```

## Next steps

<CardGroup cols={2}>
  <Card title="Templates" icon="file-lines" href="/en/templates">
    Create and send templates to reopen the window.
  </Card>

  <Card title="Actions" icon="layer-group" href="/en/action-groups/overview">
    Chain sends, labels, notes, and AI execution in one request.
  </Card>
</CardGroup>