Introducing PageSpeed optimizations
Today we've introducing a new experimental feature: Google PageSpeed optimizations support. The PageSpeed module is a suite of tools that tries to optimize web page latency and bandwidth usage of your websites by rewriting your content to implement web performance best practices. Reducing the number of requests to a single domain, optimizing cache policies and compressing content can significantly improve web performance and lead to a better user experience.
With PageSpeed optimization filters we're making it easier to apply some of these best practices, and provide a solution that efficiently and effortlessly speed up your web apps. The optimizations takes place at the load balancer level and works for all web applications no matter what framework or language you use.
As an example of how this works you can inspect the HTML and resources of this blog to see some of the optimizations that are applied. Analyzing blog.appharbor.com with the online PageSpeed insights tool yields a "PageSpeed score" of 88 when enabled versus 73 when disabled. Not too bad considering it only took a click to enable it.
You can enable PageSpeed optimizations for your web application on the new "Labs" page, which can be found in the application navigation bar. The application will be configured with PageSpeed's core set of filters within a few seconds. We will then, among other things, apply these filters to your content:
- Combine and minify CSS files.
- Extend resource caching without affecting your ability to change such resources.
- Minify javascript: Strips comments and most whitespace.
- Inline small CSS and javascript files.
- Optimize images by inlining small images, and by losslessly recompressing and resizing images.
When you've enabled PageSpeed we recommend that you test the application to make sure it doesn't break anything. You can also inspect the returned content in your browser and if you hit any snags simply disable PageSpeed and let support know about it. Note that only content transferred over HTTP from your domain will be processed by PageSpeed filters. To optimize HTTPS traffic you can enable SPDY support (although that is currently only enabled on dedicated load balancers and in the beta region).
We'll make more filters available later on, but for the beta we're starting out with a curated set of core filters, which are considered safe for most web applications. There are a few other cool filters we'll add support for later on - such as automatic sprite image generation and lazy-loading of images. Let us know if there are any filters in the catalog you think we should support!