Appwrite

Appwrite is an open-source backend platform you can self-host or use as a managed service. It provides a database, user authentication, file storage, and function hosting in one package. The REST and GraphQL APIs are auto-generated from your schema, so you can build apps without setting up infrastructure yourself.

Appwrite is a good choice for developers who want a Firebase alternative with more flexibility and control over their data. It suits both indie developers and teams building internal tools, with the option to self-host for privacy or compliance needs.