> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.voicebip.com/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.voicebip.com/_mcp/server.

# Send a message (SMS or WhatsApp)

POST https://api.voicebip.com/v1/messages
Content-Type: application/json

Sends an SMS or free-form WhatsApp message. Returns `201` with the
`Message` object; you track delivery via the `message.*` webhooks you
already receive.

The `status` field reflects how the send was handled:

* `sent` — handed to the carrier/provider synchronously (default).
* `queued` — accepted onto the carrier-safe priority lane (the platform
  paces sends within per-carrier limits) and sent as soon as there is
  headroom. SMS uses this paced path; WhatsApp free-form sends are always
  synchronous. The returned `message_id` is the id the message is sent
  under, but a `queued` message is briefly un-queryable via
  `GET /v1/messages/{message_id}` until it dispatches (sub-second), and
  its `conversation_id` is assigned then.

Reference: https://docs.voicebip.com/api/messages/send-message

## Authentication

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

## Servers

- `https://api.voicebip.com` (Production, default)
- `https://sandbox.voicebip.com` (Sandbox)

## Request

### Body (application/json)

This endpoint expects an object.

- `agent_id` (string, required)
- `channel` (enum, required)
  - Allowed values: `sms`, `whatsapp`
- `from_number` (string, required)
- `to_number` (string, required)
- `body` (string, required)
- `phone_number_id` (string, optional) — WhatsApp business phone number ID (required for WhatsApp channel)
- `message_type` (enum, optional, default: text) — Message type. Defaults to text for SMS.
  - Allowed values: `text`, `image`, `audio`, `document`, `video`, `interactive`
- `media_url` (string, optional) — URL to media file (required for non-text message_type)
- `media_caption` (string, optional) — Optional caption for images and videos

## Response

### 200

Message accepted. `status` is `sent` (synchronous) or `queued` (accepted onto the paced priority lane — delivery via `message.*` webhooks).

- `message_id` (string, optional)
- `conversation_id` (string, optional)
- `agent_id` (string, optional)
- `channel` (enum, optional)
  - Allowed values: `sms`, `whatsapp`
- `direction` (enum, optional)
  - Allowed values: `inbound`, `outbound`
- `from_number` (string, optional)
- `to_number` (string, optional)
- `body` (string, optional)
- `status` (enum, optional)
  - Allowed values: `queued`, `sent`, `delivered`, `read`, `failed`
- `segments` (integer, optional) — Number of SMS segments the message was split into. Populated for SMS channel only; null for WhatsApp.
- `created_at` (datetime, optional)
- `is_sandbox` (boolean, optional) — True when the message was created with a pk_test_ (sandbox) API key. Omitted when false.

## Examples

**Request**

```json
{
  "agent_id": "agent_id",
  "channel": "sms",
  "from_number": "from_number",
  "to_number": "to_number",
  "body": "body"
}
```

**Response**

```json
{
  "message_id": "message_id",
  "conversation_id": "conversation_id",
  "agent_id": "agent_id",
  "channel": "sms",
  "direction": "inbound",
  "from_number": "from_number",
  "to_number": "to_number",
  "body": "body",
  "status": "queued",
  "segments": 1,
  "created_at": "2024-01-15T09:30:00Z",
  "is_sandbox": true
}
```

**SDK Code**

```python
import requests

url = "https://api.voicebip.com/v1/messages"

payload = {
    "agent_id": "agent_id",
    "channel": "sms",
    "from_number": "from_number",
    "to_number": "to_number",
    "body": "body"
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.json())
```

```javascript
const url = 'https://api.voicebip.com/v1/messages';
const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: '{"agent_id":"agent_id","channel":"sms","from_number":"from_number","to_number":"to_number","body":"body"}'
};

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.voicebip.com/v1/messages"

	payload := strings.NewReader("{\n  \"agent_id\": \"agent_id\",\n  \"channel\": \"sms\",\n  \"from_number\": \"from_number\",\n  \"to_number\": \"to_number\",\n  \"body\": \"body\"\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.voicebip.com/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  \"agent_id\": \"agent_id\",\n  \"channel\": \"sms\",\n  \"from_number\": \"from_number\",\n  \"to_number\": \"to_number\",\n  \"body\": \"body\"\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.voicebip.com/v1/messages")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"agent_id\": \"agent_id\",\n  \"channel\": \"sms\",\n  \"from_number\": \"from_number\",\n  \"to_number\": \"to_number\",\n  \"body\": \"body\"\n}")
  .asString();
```

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

$client = new \GuzzleHttp\Client();

$response = $client->request('POST', 'https://api.voicebip.com/v1/messages', [
  'body' => '{
  "agent_id": "agent_id",
  "channel": "sms",
  "from_number": "from_number",
  "to_number": "to_number",
  "body": "body"
}',
  'headers' => [
    'Authorization' => 'Bearer <token>',
    'Content-Type' => 'application/json',
  ],
]);

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

```csharp
using RestSharp;

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

```swift
import Foundation

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

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

let request = NSMutableURLRequest(url: NSURL(string: "https://api.voicebip.com/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()
```