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

# Change the subscription billing interval

POST https://api.getdial.ai/api/v1/billing/subscription/change
Content-Type: application/json

Switches the subscription billing interval (e.g. upgrade monthly → annual). Prorated and invoiced immediately; the new-period entitlement lands when that invoice is paid. Clears any scheduled cancellation. No-op if already on the target interval. Not available during impersonation.

Reference: https://docs.getdial.ai/api-reference/rest-api/billing/change-subscription-interval

## Authentication

- `Authorization` header (bearer token, required) — Your Dial API key, sent as `Authorization: Bearer sk_live_...`

## Request

### Body (application/json)

- `interval` (enum, required)
  - Allowed values: `monthly`, `annual`
- `promotionCode` (string, optional) — Optional customer-facing promotion code (e.g. `LAUNCH20`) to apply to the subscription. Resolved to its Stripe promotion code and handed to Stripe, which validates it and applies the discount per the underlying coupon's own scope and duration. An invalid, expired, or inapplicable code is rejected with `400`. Preview the discounted amount first with Preview a subscription change.
- `prorationDate` (integer, optional) — Optional Unix timestamp (seconds) from a prior preview's `prorationDate`. When supplied, the proration is calculated as of that instant so the charged amount matches the previewed quote exactly. Omit to prorate as of now.

## Response

### 200

Interval change applied (or already on the target interval).

- `changed` (boolean, optional) — False when already on the target interval.
- `interval` (enum, optional)
  - Allowed values: `monthly`, `annual`

## Examples

**Request**

```json
{
  "interval": "annual"
}
```

**Response**

```json
{
  "changed": true,
  "interval": "annual"
}
```

**SDK Code**

```python
import requests

url = "https://api.getdial.ai/api/v1/billing/subscription/change"

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

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

print(response.json())
```

```javascript
const url = 'https://api.getdial.ai/api/v1/billing/subscription/change';
const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: '{"interval":"annual"}'
};

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.getdial.ai/api/v1/billing/subscription/change"

	payload := strings.NewReader("{\n  \"interval\": \"annual\"\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.getdial.ai/api/v1/billing/subscription/change")

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  \"interval\": \"annual\"\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.getdial.ai/api/v1/billing/subscription/change")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"interval\": \"annual\"\n}")
  .asString();
```

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

$client = new \GuzzleHttp\Client();

$response = $client->request('POST', 'https://api.getdial.ai/api/v1/billing/subscription/change', [
  'body' => '{
  "interval": "annual"
}',
  'headers' => [
    'Authorization' => 'Bearer <token>',
    'Content-Type' => 'application/json',
  ],
]);

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

```csharp
using RestSharp;

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

```swift
import Foundation

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

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

let request = NSMutableURLRequest(url: NSURL(string: "https://api.getdial.ai/api/v1/billing/subscription/change")! 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()
```