The HTML is heavy

Everything else waits for the HTML. It is the first thing fetched and it can't be rendered until enough of it has arrived, so a heavy document delays the text, the images and the scripts alike — and on a phone on a slow connection that is the difference between a page appearing and a visitor leaving.

Past about 500 KB of decoded HTML the cause is nearly always one of three things: the whole catalogue rendered into a page that shows twelve of it, a page builder emitting a <style> block for every element, or data inlined as JSON for a script to use later. None of them is visible in the design, and all of them are paid for on every visit.

500 KB is our rule of thumb, not a standard. There is no limit that makes a page wrong, and a long article with a lot of words is meant to be big. Google's own crawler reads far more than this. Treat it as a prompt to look, which is why it is a notice.

Look at what is actually in the file (View source, not the inspector: the inspector shows the page after scripts have run). Usually one of:

- a listing rendering every row and hiding most of them — paginate, or render what is shown; - inline <style> repeated per element — move it to a stylesheet, which is then cached for every other page; - a large inlined JSON blob — fetch it when it is needed instead.

Compression (performance.compression) shrinks what crosses the wire but not what the browser then has to parse, so it helps and doesn't cure this.