CascadiaJS 2026 · Notes
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The Request Tax: Re-evaluating 20+ Years of Web Performance Dogma

Alex Moon · WP Engine · Day 2

An intervention.

React turned 13 years old — and how we've worked has changed.

To Bundle or Not to Bundle?

How we bundle:

  • webpack, rollup
  • BUT ALSO: inlining, data URLs, sprites

Why do we bundle?

TCP was slow; HTTP/1.1 told us we had to bundle.

Caching hated it.

Code splitting invented to find a balance between bundling and caching.

HTTP Evolution

HTTP/2SPDY fixed the HTTP/1.1 problem.

But TCP is still the problem.

HTTP/3 over QUIC — fixed a lot of hard problems.

But did we actually FIX this?

Request Granularity

HTTP/1.1 is actually faster when bundling.

The more we split and make smaller, the better HTTP/3 looks.

  • HTTP/1.1 — overhead of splitting goes up
  • HTTP/3 — more consistent at delivery
HTTP/3 + caching = ❤️

Prompts

  • Average developers: OPTIMIZE for CACHING, stop stressing about the network.
  • Framework / bundler maintainers: is the default still the answer?
  • Cloudflare: can you get us more data? Can you follow up on the 2020 article on HTTP/3 performance?
  • Anyone else have cool data?
Slides