Introducing Realtime SDK

Building real-time collaboration used to mean choosing between expensive managed services with unpredictable MAU-based billing, or spending months building your own WebSocket infrastructure from scratch. Neither option is great when you just want to add presence indicators and collaborative editing to your app.

Realtime SDK is a developer-first platform for adding real-time features to any web application. It provides React hooks for presence, cursor tracking, document sync via Yjs CRDTs, and custom event broadcasting — all backed by a managed WebSocket infrastructure that scales automatically.

We designed every API around the developer experience. Adding live cursors to an existing page takes about five lines of code. Document sync integrates with any Yjs-compatible editor. And because we charge by concurrent connections rather than monthly active users, your costs scale predictably with actual usage.

Realtime SDK is available today with a free tier that includes 50 concurrent connections, unlimited rooms, and all core features. Paid plans start at $29/month for 500 connections, with a self-hosted option on Pro and Enterprise for teams that need full control over their infrastructure.