Full Optimization Checklist

Optimization Checklist

Details




Glossary:

First Byte Time Applicable Objects Time to First Byte for the page (back-end processing + redirects)
What is checked The target time is the time needed for the DNS, socket and SSL negotiations + 100ms. A single letter grade will be deducted for every 100ms beyond the target.
Keep-Alive Applicable Objects All objects that are from a domain that serves more than one object for the page (i.e. if only a single object is served from a given domain it will not be checked)
What is checked The response header contains a "keep-alive" directive or the same socket was used for more than one object from the given host
GZIP Text Applicable Objects All objects with a mime type of "text/*" or "*javascript*"
What is checked Transfer-encoding is checked to see if it is gzip. If it is not then the file is compressed and the percentage of compression is the result (so a page that can save 30% of the size of it's text by compressing would yield a 70% test result)
Compress Images Applicable Objects JPEG Images
What is checked Within 10% of a photoshop quality 50 will pass, up to 50% larger will warn and anything larger than that will fail.
The overall score is the percentage of image bytes that can be saved by re-compressing the images.
Use Progressive JPEGs Applicable Objects All JPEG Images
What is checked Each JPEG image is checked and the resulting score is the percentage of JPEG bytes that were served as progressive images relative to the total JPEG bytes.
Cache Static Applicable Objects Any non-html object with a mime type of "text/*", "*javascript*" or "image/*" that does not explicitly have an Expires header of 0 or -1, a cache-control header of "private", "no-store" or "no-cache" or a pragma header of "no-cache"
What is checked An "Expires" header is present (and is not 0 or -1) or a "cache-control: max-age" directive is present and set for an hour or greater. If the expiration is set for less 7 days you will get a warning. If the expiration is set for less than 1 hour you will get a failure. This only applies to max-age currently.
Use A CDN Applicable Objects All static non-html content (css, js and images)
What is checked Checked to see if it is hosted on a known CDN (CNAME mapped to a known CDN network). 80% of the static resources need to be served from a CDN for the overall page to be considered using a CDN. The current list of known CDN's is here