Onely November 2022 experiment (Ziemek Bućko) — brand-new zero-authority test subdomain; JS-folder page 7 took 313 HOURS vs HTML 36 hours (9x slower); first link 52h vs 25h — different stage (discovery, not render) but the high-authority/low-authority contrast is the point

Claim: Onely's November 2022 experiment (Ziemek Bućko, "Google Needs 9X More Time To Crawl JS Than HTML") ran on a brand-new, zero-authority test subdomain. Findings:

• "It took Google 313 hours to get to the final, seventh page of the JavaScript folder. With HTML, it took just 36 hours. That's nearly 9 times faster."
• At the first injected link, 52 hours (JS) vs 25 hours (HTML).

This measures a different stage from the Vercel study — JS-dependent link discovery (not render completion of an already-discovered page) — and predates the Vercel study by ~20 months, so the two are not strictly contradictory.

But the contrast is the entire point: the favourable Vercel numbers come from high-authority sites; the punishing Onely numbers come from a new, zero-authority site. That is the regime new Candid client sites sit in at launch.

Source: Onely (Ziemek Bućko), November 2022.

Confidence: Medium. Single methodologically-disclosed experiment.

Caveat: Vendor incentive flagged — Onely sells technical SEO audits and has a commercial interest in flagging JS-indexing risk. The methodology is disclosed and the result is consistent with Google's own statements that new low-authority sites have less crawl priority — see lifecycle A brand-new domain has no history, so Google has little crawl demand to work with — crawls conservatively and ramps up (or doesn't) based on what it finds and Illyes (May 2023 SEO Office Hours) — indexing speed "depends on a bunch of things, but the most important one is the quality of the site, followed by its popularity on the internet".