JavaScript-Rendered Pages

The usual sequence: a scraper returns nothing, the page looks fine in a browser, and the conclusion is "I need a headless browser".

That conclusion is wrong more often than it's right. A headless browser is 10 to 50 times slower, far heavier on memory, much more fragile, and much more detectable. Exhaust the alternatives first.

Check what you actually need

# What the server sends, before any JavaScript runs
curl -s https://example.com/page > raw.html
wc -c raw.html
grep -c "the-thing-you-want" raw.html

If your data is in raw.html, you're done — no browser needed. If it isn't, work down this list before reaching for one.

1. Hydration blobs. Most modern frameworks embed the page's data as JSON in the initial HTML.