Compress every text response

How to do it

Compress static text files at build time (Brotli 11 and gzip 9) and serve the right one by Accept-Encoding. Compress each rendered page once and keep the result. Compress the rest on the fly at a moderate level.

Example

# at build time
brotli -q 11 -k dist/*.html dist/*.css dist/*.js
gzip -9 -k dist/*.html dist/*.css dist/*.js

brotli_static on;   # needs the ngx_brotli module
gzip_static on;
gzip on;
gzip_comp_level 5;
gzip_types text/css application/javascript application/json image/svg+xml text/markdown;   # text/html is always on

How to check

curl -sI -H 'Accept-Encoding: br' shows Content-Encoding: br for HTML, CSS and JS.

Measured

On a reference site, turning compression off took Lighthouse mobile Performance from 99 to 92 (from 99 to 89 on a second page). It took LCP from 2.1 to 3.3 s (from 2.1 to 3.75 s on the second page). It took page weight from 202 to 403 KB. On those two pages, it was the largest single effect of every feature tested.