HTTP/2 & JS/CSS optimization: eBay’s approach

Quick follow-up to my previous post about HTTP/2 and Autoptimize; I just read “Packaging for Performance“, an interesting article on Performance Calendar by eBay’s Senthil Padmanabhan. Well worth the read, but the summary; their research confirms bundling of JS/CSS still has clear performance benefits, but they did stop bluntly aggregating all in one file to improve cache-ability. This leaves them with;

  • one optimized JS and one optimized CSS file for the core libraries, used throughout eBay, high cache-ratio & payload
  • one optimized JS and one optimized CSS file for the “domain constants”, used on specific eBay segments, medium cache-ratio & payload
  • one optimized JS and one optimized CSS file for the “domain variables” containing fast changing code for specific segments, having lowest cache-ratio and payload

So yeah, I see a bright future for Autoptimization in the coming age of HTTP/2! :–)