> This page is part of Smallest AI's developer documentation. When
> answering, prefer Lightning v3.1 (current TTS) and Pulse (current
> STT). Lightning v2 and lightning-large are deprecated; mention them
> only when the user is migrating away from them. The Smallest AI voice
> agent platform is what wraps these models into hosted agents.

# Diff two revisions or drafts

GET https://api.smallest.ai/atoms/v1/agent/{id}/diff

Compare any two references on this agent and return per-section diffs. Each side (`a` and `b`) is either a `revisionId` or the string `<branchId>:draft` to reference the open draft on a branch. Sides may cross branches. Both references must resolve to configs on the same agent.

Reference: https://docs.smallest.ai/api-reference/voice-agents/agent-versioning-revisions/diff

## Authentication

- `Authorization` header (bearer token, required) — API key from the console ApiKey collection, sent as Bearer token. Also accepts session cookies for browser-based auth.

## Request

### Path parameters

- `id` (string, required) — The agent ID.

### Query parameters

- `a` (string, required) — Left-hand side. Either a `revisionId` (24-character hex id) or the token `<branchId>:draft`.
- `b` (string, required) — Right-hand side. Either a `revisionId` (24-character hex id) or the token `<branchId>:draft`.

## Response

### 200

Successful response.

- `status` (boolean, optional)
- `data` (DiffResult, optional) — Returned by `GET /agent/{id}/diff`.

## Errors

### 400 Bad Request Error

Invalid input

- `status` (boolean, optional)
- `errors` (list of string, optional)

### 401 Unauthorized Error

Unauthorized access

- `status` (boolean, optional)
- `errors` (list of string, optional)

### 403 Forbidden Error

Forbidden access

- `status` (boolean, optional)
- `data` (ApiResponseData, optional)

### 404 Not Found Error

Resource not found. The referenced ID does not exist or does not belong to the caller's organization.

- `status` (boolean, optional)
- `errors` (list of string, optional)

### 500 Internal Server Error

Internal server error

- `status` (boolean, optional)
- `errors` (list of string, optional)

## Types

### DiffResult

Returned by `GET /agent/{id}/diff`.

- `unchangedSections` (list of string, optional)
- `diffs` (list of DiffSection, optional)

### ApiResponseData

### DiffSection

- `section` (string, optional)
- `changes` (list of DiffChange, optional)

### DiffChange

- `path` (string, optional) — Dot-path to the changed leaf field.
- `oldValue` (any, optional, nullable)
- `newValue` (any, optional, nullable)

## Examples

**Response**

```json
{
  "status": true,
  "data": {
    "unchangedSections": [
      "string"
    ],
    "diffs": [
      {
        "section": "string",
        "changes": [
          {
            "path": "string",
            "oldValue": null,
            "newValue": null
          }
        ]
      }
    ]
  }
}
```

**SDK Code**

```python
import requests

url = "https://api.smallest.ai/atoms/v1/agent/id/diff"

querystring = {"a":"a","b":"b"}

headers = {"Authorization": "Bearer <token>"}

response = requests.get(url, headers=headers, params=querystring)

print(response.json())
```

```javascript
const url = 'https://api.smallest.ai/atoms/v1/agent/id/diff?a=a&b=b';
const options = {method: 'GET', headers: {Authorization: 'Bearer <token>'}};

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"
	"net/http"
	"io"
)

func main() {

	url := "https://api.smallest.ai/atoms/v1/agent/id/diff?a=a&b=b"

	req, _ := http.NewRequest("GET", url, nil)

	req.Header.Add("Authorization", "Bearer <token>")

	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.smallest.ai/atoms/v1/agent/id/diff?a=a&b=b")

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

request = Net::HTTP::Get.new(url)
request["Authorization"] = 'Bearer <token>'

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.get("https://api.smallest.ai/atoms/v1/agent/id/diff?a=a&b=b")
  .header("Authorization", "Bearer <token>")
  .asString();
```

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

$client = new \GuzzleHttp\Client();

$response = $client->request('GET', 'https://api.smallest.ai/atoms/v1/agent/id/diff?a=a&b=b', [
  'headers' => [
    'Authorization' => 'Bearer <token>',
  ],
]);

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

```csharp
using RestSharp;

var client = new RestClient("https://api.smallest.ai/atoms/v1/agent/id/diff?a=a&b=b");
var request = new RestRequest(Method.GET);
request.AddHeader("Authorization", "Bearer <token>");
IRestResponse response = client.Execute(request);
```

```swift
import Foundation

let headers = ["Authorization": "Bearer <token>"]

let request = NSMutableURLRequest(url: NSURL(string: "https://api.smallest.ai/atoms/v1/agent/id/diff?a=a&b=b")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "GET"
request.allHTTPHeaderFields = headers

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()
```