> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.agentphone.ai/api-reference/messages/send-message-v-1-messages-post/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.agentphone.ai/_mcp/server.

# Send Message

POST https://api.agentphone.ai/v1/messages
Content-Type: application/json

Send an outbound message (SMS, iMessage, or WhatsApp) via the provider assigned to the number.

WhatsApp sends need `channel: "whatsapp"` and are subject to Meta's 24-hour customer service window: a free-form message only reaches someone who messaged you in the last 24 hours, and outside that window you need an approved `template`. WhatsApp also unlocks `buttons`, `list`, and `cta`. See the [WhatsApp guide](/documentation/guides/whatsapp) for the full rules.

Attach media by passing public HTTPS URLs in `media_urls` (1-20 per message). Text and media can be combined: pass `body` alongside any number of attachments. Every message needs text, media, or both; for a media-only message, pass an empty `body` (`""`).

Media rules:
- Each URL must be a **publicly accessible HTTPS link**
- Group chats and WhatsApp support one attachment per message
- On iMessage-capable numbers, 2-20 image URLs are delivered as an image carousel

> **Deprecation notice:** The `media_url` field (singular) is deprecated and will be removed in a future version. Use `media_urls` (array) instead, even for a single attachment: `media_urls: ["https://..."]`.

Reference: https://docs.agentphone.ai/api-reference/messages/send-message-v-1-messages-post

## Authentication

- `Authorization` header (bearer token, required) — Bearer authentication of the form `Bearer <token>`, where token is your auth token.

## Request

### Body (application/json)

This endpoint expects a SendMessageRequest.

- `body` (string, required)
- `agent_id` (string, optional, nullable)
- `to_number` (string, optional, nullable) — Recipient of an existing chat: a phone (any format, normalized to E.164), US short code, email, or a group id (grp_...). Provide this OR `recipients` (to start a new group), not both.
- `recipients` (list of string, optional, nullable) — Start a NEW iMessage group by listing 2 or more recipients (phones or emails). The first message is delivered to all of them, an iMessage group is created, and the response `to_number` returns the new group id (grp_...) to use for follow-up sends. iMessage numbers only.
- `media_url` (string, optional, nullable)
- `media_urls` (list of string, optional, nullable)
- `number_id` (string, optional, nullable)
- `from_number` (string, optional, nullable)
- `channel` (enum, optional) — Optional transport override for numbers connected to multiple channels. Pass "whatsapp" to send via the number's WhatsApp connection instead of its default SMS/iMessage transport. WhatsApp-only numbers use WhatsApp automatically.
  - Allowed values: `whatsapp`
- `send_style` (enum, optional) — Optional iMessage expressive effect. Only valid on iMessage-capable numbers. Supported values: celebration, fireworks, lasers, love, confetti, balloons, spotlight, echo, invisible, gentle, loud, slam.
  - Allowed values: `celebration`, `fireworks`, `lasers`, `love`, `confetti`, `balloons`, `spotlight`, `echo`, `invisible`, `gentle`, `loud`, `slam`
- `reply_to_message_id` (string, optional, nullable) — Optional parent message ID (AgentPhone Message.id) to send this message as an inline reply. Supported on iMessage and WhatsApp; the parent must be in the same chat and sent from the same number.
- `buttons` (list of string, optional, nullable) — WhatsApp only: up to 3 tappable reply buttons (each max 20 chars). The tapped button's text arrives as a normal inbound message. Pass media_urls alongside buttons to render that image, video, or document as a header above the text, in the same bubble as the buttons (audio has no header form and is rejected).
- `list` (SendMessageRequestList, optional, nullable) — WhatsApp only: a tap-to-open list menu. \{"button": "View options", "options": \["Small", "Medium", "Large"]} (max 10 options, 24 chars each), or full form with sections: \{"button": str, "sections": \[\{"title": str, "rows": \[\{"id": str, "title": str, "description": str}]}]}.
- `cta` (SendMessageRequestCta, optional, nullable) — WhatsApp only: a single tappable link button on an ordinary message. \{"display\_text": "Track order", "url": "[https://example.com/t/123](https://example.com/t/123)", "footer": "Tap to see live status"} — `footer` is optional. The url must be absolute and https. Unlike a URL button on a template this needs no Meta review, but as an ordinary message it only reaches someone inside the 24h window.
- `template` (SendMessageRequestTemplate, optional, nullable) — WhatsApp only: send a Meta-approved message template. This is the only way to reach someone outside the 24h customer service window. \{"name": "order\_shipped", "language": "en\_US", "variables": \["1234"]} — `variables` fill the template body, and `header_variables` does the same for a text header. Pass an array for a POSITIONAL template (\{\{1}}, \{\{2}}) or an object for a NAMED one, e.g. \{"variables": \{"first\_name": "Pablo"}} for a body reading "Thanks \{\{first\_name}}!". The shape must match how the template was authored. `language` defaults to en\_US. The template must already be APPROVED (see the templates endpoints). `body` is NOT delivered for template sends — WhatsApp renders the approved template content — it is kept only as a fallback label if we can't render the template for your message history.

## Response

### 200

Successful Response

- `id` (string, required)
- `status` (string, required)
- `channel` (string, required)
- `from_number` (string, required)
- `to_number` (string, required)
- `conversation_id` (string, optional, nullable)
- `media_urls` (list of string, optional, default: [])
- `reply_to_message_id` (string, optional, nullable)
- `reply_parent_unresolved` (boolean, optional, nullable)

## Errors

### 422 Unprocessable Entity Error

Validation Error

- `detail` (list of ValidationError, optional)

## Types

### SendMessageRequestList

WhatsApp only: a tap-to-open list menu. \{"button": "View options", "options": \["Small", "Medium", "Large"]} (max 10 options, 24 chars each), or full form with sections: \{"button": str, "sections": \[\{"title": str, "rows": \[\{"id": str, "title": str, "description": str}]}]}.

### SendMessageRequestCta

WhatsApp only: a single tappable link button on an ordinary message. \{"display\_text": "Track order", "url": "[https://example.com/t/123](https://example.com/t/123)", "footer": "Tap to see live status"} — `footer` is optional. The url must be absolute and https. Unlike a URL button on a template this needs no Meta review, but as an ordinary message it only reaches someone inside the 24h window.

### SendMessageRequestTemplate

WhatsApp only: send a Meta-approved message template. This is the only way to reach someone outside the 24h customer service window. \{"name": "order\_shipped", "language": "en\_US", "variables": \["1234"]} — `variables` fill the template body, and `header_variables` does the same for a text header. Pass an array for a POSITIONAL template (\{\{1}}, \{\{2}}) or an object for a NAMED one, e.g. \{"variables": \{"first\_name": "Pablo"}} for a body reading "Thanks \{\{first\_name}}!". The shape must match how the template was authored. `language` defaults to en\_US. The template must already be APPROVED (see the templates endpoints). `body` is NOT delivered for template sends — WhatsApp renders the approved template content — it is kept only as a fallback label if we can't render the template for your message history.

### ValidationError

- `loc` (list of ValidationErrorLocItems, required)
- `msg` (string, required)
- `type` (string, required)

### ValidationErrorLocItems

## Examples

**Request**

```json
{
  "body": "string"
}
```

**Response**

```json
{
  "id": "string",
  "status": "string",
  "channel": "string",
  "from_number": "string",
  "to_number": "string",
  "conversation_id": "string",
  "media_urls": [
    "string"
  ],
  "reply_to_message_id": "string",
  "reply_parent_unresolved": true
}
```

**SDK Code**

```python
import requests

url = "https://api.agentphone.ai/v1/messages"

payload = { "body": "string" }
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.json())
```

```javascript
const url = 'https://api.agentphone.ai/v1/messages';
const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: '{"body":"string"}'
};

try {
  const response = await fetch(url, options);
  const data = await response.json();
  console.log(data);
} catch (error) {
  console.error(error);
}
```

```go
package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.agentphone.ai/v1/messages"

	payload := strings.NewReader("{\n  \"body\": \"string\"\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}
```

```ruby
require 'uri'
require 'net/http'

url = URI("https://api.agentphone.ai/v1/messages")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"body\": \"string\"\n}"

response = http.request(request)
puts response.read_body
```

```java
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.Unirest;

HttpResponse<String> response = Unirest.post("https://api.agentphone.ai/v1/messages")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"body\": \"string\"\n}")
  .asString();
```

```php
<?php
require_once('vendor/autoload.php');

$client = new \GuzzleHttp\Client();

$response = $client->request('POST', 'https://api.agentphone.ai/v1/messages', [
  'body' => '{
  "body": "string"
}',
  'headers' => [
    'Authorization' => 'Bearer <token>',
    'Content-Type' => 'application/json',
  ],
]);

echo $response->getBody();
```

```csharp
using RestSharp;

var client = new RestClient("https://api.agentphone.ai/v1/messages");
var request = new RestRequest(Method.POST);
request.AddHeader("Authorization", "Bearer <token>");
request.AddHeader("Content-Type", "application/json");
request.AddParameter("application/json", "{\n  \"body\": \"string\"\n}", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
```

```swift
import Foundation

let headers = [
  "Authorization": "Bearer <token>",
  "Content-Type": "application/json"
]
let parameters = ["body": "string"] as [String : Any]

let postData = JSONSerialization.data(withJSONObject: parameters, options: [])

let request = NSMutableURLRequest(url: NSURL(string: "https://api.agentphone.ai/v1/messages")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "POST"
request.allHTTPHeaderFields = headers
request.httpBody = postData as Data

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error as Any)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()
```