Tuesday, February 24, 2009

New! Grow your app beyond the free quotas!

We're psyched to announce that developers can now purchase additional computing resources on App Engine, enabling apps to scale beyond our free quotas. This has been our most requested improvement to App Engine and we're thrilled to deliver it, as promised.

When we released App Engine last April, it was completely free to use, but each application was limited to a set of fixed resource usage quotas. The free quotas are still there, but now you can grow beyond them.

You can now set a daily budget for your app that represents the maximum amount you're willing to pay for computing resources each day. You allocate this budget across CPU, bandwidth, storage, and email, and you pay for only what your app consumes beyond the free thresholds -- prorated up to the nearest penny. We've put together a handy screencast to help explain the process:

App Engine remains free to get started. However, along with many performance improvements over the past ten months, we've learned that we overestimated our initial free quota values. Therefore, in 90 days we will be reducing the free quota resources. We believe these new levels will continue to support a reasonably efficient application serving around 5 million page views per month, completely free.

The pricing for resources beyond those free quotas is:

  • $0.10 per CPU core hour. This covers the actual CPU time an application uses to process a given request, as well as the CPU used for any Datastore usage.
  • $0.10 per GB bandwidth incoming, $0.12 per GB bandwidth outgoing. This covers traffic directly to/from users, traffic between the app and any external servers accessed using the URLFetch API, and data sent via the Email API.
  • $0.15 per GB of data stored by the application per month.
  • $0.0001 per email recipient for emails sent by the application

Data stored in the datastore incurs additional overhead, depending on the number of indexes, as well as the number (and size) of associated properties. This overhead can be significant in some cases, and it's something that we have been underreporting up until now. Thus, you may notice an increase in the amount of data stored by your application that is listed in the Admin Console.

To decrease the impact of this change in the way we calculate storage usage, we've doubled the free storage quota to 1GB. To learn more about how our quotas work, upcoming changes to our quota levels, how they relate to billing, and overall resource consumption limitations, see the Quotas section of the docs. The Purchasing Additional Quota section has more detail about how to purchase additional computational resources for your app, and there's also a Billing FAQ. We've also made some changes to our terms of service to include language around payments, fees, and disallowing the use of multiple applications to avoid incurring fees.

As always, we welcome feedback in our discussion group, and don't forget to check out the App Engine sessions at our upcoming developer conference, Google I/O!