Magento – How to create and use REST API for mobile app

Route must look like this rest/api/categories and not just /categories

Now it's resources that fails, so I will provide a full copy, if I get there :)

Thanks Marius for input

$url = 'magentohost url';
$callbackUrl = $url . "oauth_admin.php";
$temporaryCredentialsRequestUrl = $url . "oauth/initiate?oauth_callback=" . urlencode($callbackUrl);
$adminAuthorizationUrl = $url . 'admin/oauth_authorize';
$accessTokenRequestUrl = $url . 'oauth/token';
$apiUrl = $url . 'api/rest';
$consumerKey = 'consumer_key';
$consumerSecret = 'consumer_secret';
$token = 'token';
$secret = 'token_secret';

try {
    $oauthClient = new OAuth($consumerKey, $consumerSecret, OAUTH_SIG_METHOD_HMACSHA1, OAUTH_AUTH_TYPE_AUTHORIZATION);
    $oauthClient->setToken($token, $secret);
    $resourceUrl = "$apiUrl/products";
    $oauthClient->fetch($resourceUrl, array(), 'GET', array('Content-Type' => 'application/json', 'Accept' => 'application/json'));
    $productsList = json_decode($oauthClient->getLastResponse());
    echo '<pre>';
    print_r($productsList);
}
catch(Exception $e) {
    echo '<pre>';
    print_r($e);
}

• Source: https://stackoverflow.com/questions/28688904/magento-rest-api-is-giving-only-10-products