Last year Parse launched in private beta, offering a way for mobile app developers to focus on what they’re good at — making killer apps — without having to worry about all the messy server-side code that might not come as naturally. Since so many mobile apps share common elements on the backend, the San Francisco-based startup was essentially doing away with the need for developers to rebuild the same code over and over again every time they built a new app.

By using the Parse SDK, developers can quickly get up and running on its platform, allowing it to manage things like databases, user authentication, push notifications, and even file storage for many items. It’s already being used by thousands of developers since introducing its private beta.

Now Parse is making its mobile backend-as-a-service offering available to anyone who wish to use it. The service is going live with a revenue model Monday that will essentially allow developers to build and test out apps for free, only having to pay once they reach a certain number of API requests, push notifications or file storage.

Parse customers get up to 1 million API requests, 1 million push notifications and 1 GB of storage for free. Once they go over those limits, they can pay overages of 7 cents per thousand API requests or push notifications, or 20 cents per extra GB of storage used. Or they can upgrade to Parse’s Pro service for $199 a month, which gives them 15 million API requests, 5 million push notifications and 5 GB of storage. Overages for the number of API requests or push notifications on the Pro plan run 5 cents per 1,000, with extra storage available for 15 cents per GB.

Parse was part of YCombinator’s Summer 2011 class, and has raised a total of $7 million through a $1.5 million seed round and a $5.5 million Series A round led by Ignition Partners. The startup