My knowledge:

• HTML & CSS (Bootstrap)
• JavaScript
• Php
• Java
• Dart (Flutter)
• MySQL (MariaDB, PostgresSQL, MongoDB, SQLite)
• Firebase (Database Realtime, Cloud Messaging - Notification Push)
• JSON & XML (RSFeed)
• WordPress (I've also used the rest of WordPress API)

You can see more projects on my website, but it is currently under construction.
http://www.twitter.com/DomingoMG97