WTF is... backend-as-a-service?

It was only a matter of time until a company like Firebase appeared, saw some success, and went into general availability, but that isn't helping with the nauseous term for its tech: backend-as-a-service.

Software-as-a-service? Sure. Infrastructure? Bit expensive, but fine. Database? Mad idea, but okay if you have a lot of stuff up there. Platform? If you don't mind having very little idea of what's going on, righto. Backend? What?

For all our incredulity that hasn't stopped backend-as-a-service startup Firebase announcing the general availability of its product on Thursday, and putting a pricing option in place.

The company's BaaS technology gives developers a way to update the same application across multiple devices in milliseconds. The company says it replaces "the request/response model of traditional backends with a new approach based on data synchronization".

It does this by maintaining persistent SSL-encrypted TCP connections between devices and Firebase's servers, allowing clients to push data in both directions across the public internet.

"You can send data to other clients without them needing to request it. You also get a stateful connection [so] we're maintaining state on the client," CTO Andrew Lee tells The Register.

Though Firebase's technology is not new - Google and Facebook and other companies operate internal systems like this, which allow services like Google Docs to replicate out to sync updates across multiple distributed clients in a short amount of time – Firebase believes it is the first company of its kind to expose the technology as an API.

"The key word is general purpose," Lee says. "There's nothing about what we're doing technically that has not been done before, but not as something people could see. We've pulled out this use case of sharing structured [JSON] data in real time."

Where infrastructure-as-a-service gives you access to a VM that acts like it is an individual server, and platform-as-a-service gives you access to a (usually language-specific) runtime environment, a backend-as-a-service gives you an API into a common infrastructure for sending data between applications.

Potential use cases include programming environments for teams working at a distance, games, snappy chat rooms, and "any application where you want a change made by one user to be visible to other users immediately."

Firebase's service was previously based on an unnamed cloud provider, but the company is now hosted by IBM-acquired SoftLayer's SSD-backed cloud.

With general availability, Firebase has also introduced a pricing option for its service, which was previously free. The $49 per month "Candle" option gives developers 20GB of data transfer, 200 connections, and 3GB of data storages. Greater capacities are available via the "Bonfire", "Blaze", and "Inferno" options.

The free "Candlestick", by comparison, gives devs access to 5GB of data transfer, up to 50 connections, and 100MB of data storage. ®