Pocketbase

PocketBase offers a complete open-source backend solution conveniently packaged within a single executable file. This makes it incredibly portable and easy to set up, providing a ready-to-use system right out of the box. It's designed to be an all-in-one solution for your next project, whether it's a small hobby app or a full-scale production service.

Key features include:

• Realtime Database: An embedded, high-performance database complete with a schema builder, data validations, and a simple REST API for easy data management.
• Built-in Authentication: Handle user sign-ups and management effortlessly with support for both email/password and OAuth2 providers like Google, Facebook, and GitHub.
• File Storage: Store files locally or in an S3-compatible service. You can easily attach media to database records and generate thumbnails on the fly.
• Admin Dashboard: A clean and functional admin UI is included, allowing you to manage your application without writing any code.

PocketBase is also highly extendable. You can use it as a standalone app or as a Go framework, extending its functionality with custom hooks in Go or JavaScript.