Mastering The Faster Web with PHP, MySQL, and JavaScript

Header compression

SPDY's third important feature was header compression with gzip. By compressing the often high number of HTTP headers and reducing them by as much as 85% of their original sizes on average, SPDY could cut up to a full second off the load time of most HTTP transactions over the wire. Although the use of gzip to dynamically compress the headers was revealed to be unsafe, the idea of header compression remained and was re-implemented in the HTTP/2 protocol due to its great benefits to overall web performance.