Begin with REST API – Display others blogs latest posts

// connect to the website endpoint with wp_remote_get() function
// pass params as URL query args, full parameter list is here https://developer.wordpress.org/rest-api/reference/posts/
// at this moment you can use any parameter with Context: View
// it would be strange if you can fetch drafts or private posts, right?
$response = wp_remote_get( add_query_arg( array(
	'per_page' => 2
), 'https://ma.tt/wp-json/wp/v2/posts' ) );

if( !is_wp_error( $response ) && $response['response']['code'] == 200 ) {

	$remote_posts = json_decode( $response['body'] ); // our posts are here
	foreach( $remote_posts as $remote_post ) {

		// display post titles and excerpts
		echo '<h2>'. $remote_post->title->rendered . '</h2><p>' . $remote_post->excerpt->rendered . '</p>';
		// need more parameters? print_r( $remote_post )
		
	}
}

// trying to get value from the cache
if( false == $allposts = get_transient( 'misha_remote_cache' ) ) {
	
	// it will be the array with all posts
	$allposts = array();
	
	// get the first website latest posts
	$blog1 = wp_remote_get( 'https://ma.tt/wp-json/wp/v2/posts?per_page=2' );
 
	if( !is_wp_error( $blog1 ) && $blog1['response']['code'] == 200 ) {
 
		$remote_posts = json_decode( $blog1['body'] ); // our posts are here
		foreach( $remote_posts as $remote_post ) {
 
			// I decided to create array like $allposts[1504838841] = Object
 			$allposts[ strtotime( $remote_post->date_gmt ) ] = $remote_post;
		
		}
	}

	// get the second website latest posts
	$blog2 = wp_remote_get( 'https://css-tricks.com/wp-json/wp/v2/posts?per_page=2' );
 
	if( !is_wp_error( $blog2 ) && $blog2['response']['code'] == 200 ) {
 
		$remote_posts = json_decode( $blog2['body'] ); // our posts are here
		foreach( $remote_posts as $remote_post ) {
 
 			$allposts[ strtotime( $remote_post->date_gmt ) ] = $remote_post;
		
		}
	}
		
	// sort array by keys in descending order
	krsort( $allposts );

	// store cache
	set_transient( 'misha_remote_cache', $allposts, 60 ); // for 1 minute in this example
		
}

// print posts
foreach( $allposts as $remote_post ) {
	echo '<h2>'.$remote_post->title->rendered.'</h2><p>' . $remote_post->date_gmt . '</p>';
}