Getting CURL post parameters right (PHP) - php

Question

I'm trying to send a post request to the linkedin API using CURL. For some reason I get a response saying that I'm missing one variable.
array:2 [▼
"error" => "missing_parameter"
"error_description" => "A required parameter "client_id" is missing"
]
Here is my code and I can assure you that cliend_id is set.
$code = $request->get("code");
$state = $request->get("state");
$redirect_uri = "http://example.com/linkedin/callback";
$client_id = "1242435657";
$client_secret = "XXXXXXXXXX";
$url = "https://www.linkedin.com/oauth/v2/accessToken";
$params = array(
"grant_type" => 'authorization_code',
"code" => $code,
"redirect_uri" => $redirect_uri,
"client_id" => $client_id,
"client_secret" => $client_key,
);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, $params);
$output = curl_exec($ch);
$info = curl_getinfo($ch);
curl_close($ch);
// create an array from the data that is sent back from the API
$result = json_decode($output, 1);
Is there anyway that I could debug this post request?

Answer 1

Remove the comma at the end of the last property and try again perhaps?
$params = array(
"grant_type" => 'authorization_code',
"code" => $code,
"redirect_uri" => $redirect_uri,
"client_id" => $client_id,
"client_secret" => $client_key, <=========
);