Google Cloud PostgreSQL - Fully-managed database service
Firebase - Firebase is a cloud service designed to power real-time, collaborative applications for mobile and web.
Supabase - An open source Firebase alternative
SQL playground - Create a private PostgreSQL database with a predefined structure & test data in the shortest time.
RemoteStorage - An open protocol for per-user storage OWN YOUR DATA
Hasura - Hasura is an open platform to build scalable app backends, offering a built-in database, search, user-management and more.