PocketBase

A single Go executable that packages a SQLite database, an authentication system, file storage and a realtime WebSocket layer into one deployable binary with a built-in admin interface. Data is organized as collections and records, and API rules decide which requests may read or write, so you can expose exactly the parts of your schema you want.

Small teams use it for prototypes, side projects and internal tools that need accounts and uploads without standing up a separate database, and it can be extended with Go or JavaScript hooks.

Deploying it yourself keeps users, files and records inside your own perimeter, avoids per-user licensing fees as the audience grows, and makes the whole backup a matter of copying one SQLite file.