Firebase is an online service that you can use to build realtime web apps including collaboration tools and multiplayer games without worrying about servers or writing server code.

Evolve, the company behind Firebase, has been running a beta of the software since last year. In that time, it has made the platform open to all developers and released software development kits for iOS and Android.

Firebase is a backend that replaces the request/response model of traditional backends with a new approach based on data synchronization. Essentially it is an API that you can access from JavaScript code in your application.

The Firebase service then handles the back-end, providing your front-end with persistent and shared real-time data. All the code runs in the client browser or phone app. This overcomes the problem encountered in cloud-based code where it’s difficult to scale for many users because the code needs to be sharded across multiple servers.

The service merges data storage and data transfer into a single system. The software handles all the data synchronization for collaborative work. All client communications are moved to the central data repository in the cloud. This means that if your app handles chat between multiple people, for example, Firebase doesn’t send the text of the chat to the different clients; instead, it is all sent to a repository that the clients all work with. When one client updates the repository by typing something into their chat window, the changes are synchronized across all the clients so everyone sees the same information.

On the Firebase How It Works page You can also try an interactive demo where you draw in one window and see what you’ve drawn replicated in another window. The synchronized data is also persisted, allowing new clients to be updated. The Firebird API handles the scaling to ensure clients are kept in sync, and Evolve says your app will scale from its first user to its first million without any code changes.

Data is stored as standard JSON, and the Firebase client libraries and REST API provide access to the data. If the network connection is lost, the user continues with locally cached data then resynchronized with the cloud when the device comes back online.

The move to the released version has been accompanied by a move to a chargeable model. There’s a free tier for development and small production apps with up to 50 connections, 5GB data transfer and 200MB data storage. The paid tiers start at $49 per month and go up as far as $1499 per month for up to 10,000 connections and 1,000 GB data transfer.