Example api function call using wp functions

example.php

<?php
$result = my_api_func( 'https:api....', array( 'arg1' => 'value1' ), true );
if ( is_wp_error( $result ) ) {
	// error
}

/**
 * @param $url
 * @param array $args
 * @param bool $json_decode
 *
 * @return array|mixed|object|string|WP_Error
 */
function my_api_func( $url, $args = array(), $json_decode = true ) {
	global $wp_version;

	$url = add_query_arg(
		$args,
		$url
	);

	$http_url = $url;
	if ( $ssl = wp_http_supports( array( 'ssl' ) ) ) {
		$url = set_url_scheme( $url, 'https' );
	}

	$http_args = array(
		'user-agent' => 'WordPress/' . $wp_version . '; ' . home_url( '/' ),
	);
	$request   = wp_remote_get( $url, $http_args );

	if ( $ssl && is_wp_error( $request ) ) {
		if ( ! wp_doing_ajax() ) {
			trigger_error(
				'An unexpected error occurred. Something may be wrong with this server&#8217;s configuration.',
				headers_sent() || WP_DEBUG ? E_USER_WARNING : E_USER_NOTICE
			);
		}
		$request = wp_remote_get( $http_url, $http_args );
	}

	if ( is_wp_error( $request ) ) {
		$res = new WP_Error(
			'my_api_failed',
			'An unexpected error occurred. Something may be wrong with this server&#8217;s configuration.',
			$request->get_error_message()
		);
	} else {
		if ( $json_decode ) {
			$res = json_decode( wp_remote_retrieve_body( $request ), true );
			if ( is_array( $res ) ) {
				// Object casting is required
				$res = (object) $res;
			} elseif ( null === $res ) {
				$res = new WP_Error(
					'my_api_failed',
					'An unexpected error occurred. Something may be wrong with this server&#8217;s configuration.',
					wp_remote_retrieve_body( $request )
				);
			}
		} else {
			// Check the response code
			$response_code    = wp_remote_retrieve_response_code( $request );
			$response_message = wp_remote_retrieve_response_message( $request );

			if ( 200 != $response_code && ! empty( $response_message ) ) {
				return new WP_Error( $response_code, $response_message );
			} elseif ( 200 != $response_code ) {
				return new WP_Error( $response_code, 'Unknown error occurred' );
			}
			$res = wp_remote_retrieve_body( $request );
		}

		if ( isset( $res->error ) ) {
			$res = new WP_Error( 'my_api_failed', $res->error );
		}
	}

	return $res;
}