Instant

Instant is an open-source backend for web and mobile apps. Its client SDKs, installed from npm, read and write a relational data model through queries that update as the data changes, so other clients see a change in real time and an app keeps working offline. Auth, permissions, file storage, presence and streams are part of the same service.

The server is a sync server written in Clojure that runs on the JVM. It keeps user data as triples in one PostgreSQL database and watches the database’s write-ahead log to decide which queries to refresh. The self-hosting guide describes a docker compose setup that runs Instant beside PostgreSQL, MinIO for files and Caddy as the reverse proxy, and it asks for an email provider so that login codes reach users.

Worth knowing

Instant Cloud, the hosted service, no longer accepts new signups and is scheduled to shut down. The project states that all of Instant is open source and publishes a migration guide for moving a cloud app to a self-hosted instance. Until an email provider is configured, login codes are written to the backend logs.