instantdb/instant

Instant is a backend service for building web and mobile apps that need real-time data, without the typical setup burden. Instead of building a separate server, writing API endpoints, managing caches, and syncing state between users, Instant puts a database-like interface directly in the frontend code. You write queries that describe the data shape you want, and Instant takes care of fetching, caching, syncing, and permission checking automatically. The core idea is that most of the repetitive work in modern app development is really a database problem in disguise. Stores, selectors, endpoints, and local caches are all things developers build to paper over the gap between the server database and the UI. Instant collapses that gap by giving your frontend code a query interface that stays in sync across all connected users in real time. When one user updates data, every other user seeing that data sees the change immediately, without any extra code to write. The query language is called InstaQL and looks similar to GraphQL: you describe nested relationships, and Instant returns the matching data. Writes use transactions that support optimistic updates, meaning the UI reflects your change immediately while the confirmation travels to the server in the background, with automatic rollback if something goes wrong. Ephemeral data like cursor positions and presence indicators (who is online right now) is also supported. Instant provides built-in authentication, permission rules, and file storage. SDKs are available for plain JavaScript, React, and React Native. Signing up on instantdb.com is the standard way to start, and a functional app can be running within a few minutes using the free tier.