When using the explicit oath authentication for stack apps, I have problem recieving the access_token. A user goes to /approve and is then forwarded to approve the app. When redirected back to my site I catch the code parameter and do the final POST to get the access_token. However I cant find it in the response object!

This is my php routes file:

    use GuzzleHttp\Client;

    Route::get('/approve', function () {
        header('Location: https://stackexchange.com/oauth?client_id=12345&scope=write_access&redirect_uri=https://mysite.com/approved');
    });

    Route::get('/approved', function (Request $request) {
        $client = new Client();    
        $response = $client->request('POST', 'https://stackexchange.com/oauth/access_token/json', [
            'form_params' => [
                'client_id' => 12345,
                'client_secret' => 'apfeusenfpuansefpunapfn((',
                'code' => \Request::get("code"),
                'redirect_uri' => 'https://mysite.com/approved'
            ]
        ]);

        dd($response); // dumping the response gives no trace of access_token
    });

* Running getStatusCode() on the response object gives a 200 All ok.
* Dumping the full response, body, or headers give me no reference of the access_token whatsoever.
* I tried swapping "form_params" to "query" same result. 
* Adding "json" to api url no change.
* Im using Guzzle 6

Any ideas, where did I go wrong?