Ask HN: Scaling a targeted web crawler beyond 500M pages/day

I've been reading up on crawler architecture. The two most useful sources I've found are the blog post "Crawling a billion web pages in just over 24 hours, in 2025" and the Mercator paper ("Mercator: A Scalable, Extensible Web Crawler").

Both of these, and most other material I've come across, focus on crawling the broad open web rather than a targeted set of domains. For product prices it's the latter. Mercator calls out DNS resolution as a major bottleneck, for example, but when you're only hitting a few hundred domains that isn't really a concern.

The other gap is that both assume static HTML. For our use case we need a headless browser, and we also have to deal with Cloudflare and similar anti-bot systems.

For product prices specifically, a lot of sites publish price feeds which simplifies things, but plenty don't, and getting good coverage still requires scraping. Our current system does about 500M pages/day and we're looking to improve its performance.

Does anyone here have experience in this space, or know of articles/blog posts on scaling targeted (rather than broad) crawlers with headless browsers? Any pointers appreciated.