FAQ
Questions worth answering upfront
What is 436.io, exactly?
A tool that scans every page of a website with Google PageSpeed Insights and turns the results into one short, ranked report of what to fix first, instead of a separate score per page.
Is 436.io affiliated with Google?
No. 436.io is an independent, unofficial tool built on top of the public PageSpeed Insights API. "PageSpeed Insights" and "Lighthouse" are trademarks of Google LLC.
Do I need my own API key?
No. 436.io runs on a shared server key with its own rate limits, so you can scan a site without creating a Google Cloud project or pasting a key into a form.
Is it free? Are there limits?
Yes, it is free with no login. To keep it usable for everyone, scans are capped in size and each connection is rate-limited. If a scan is refused because of a limit, it will say so and suggest trying again shortly.
What is the Actionable Report, and how is it different from Detailed Results?
The Actionable Report is the default view after a scan: a website-level summary plus the handful of recurring problems worth fixing first, each with impact, effort and how many pages it affects. Detailed Results is the full page-by-page breakdown underneath it, for when you need to dig into one specific URL.
How does 436.io decide what to fix first?
Each finding is scored from its impact, how many pages it affects, whether it touches a Core Web Vital and how much effort it typically takes to fix. A high-impact, low-effort problem affecting most of the site will usually outrank a smaller problem that is expensive to fix, even if fewer pages are involved. The same scan data always produces the same ranking.
Should I scan a website URL or upload a sitemap?
Scanning a website URL is the quickest option: 436.io looks for /sitemap.xml and any sitemap listed in robots.txt automatically. Upload a sitemap directly if the site does not expose one publicly, or if you already have the exact file you want scanned.
What happens if some pages fail to scan?
The report is built only from pages that completed successfully, and it says so plainly, for example "120 pages analyzed, 7 failed". Failed pages are listed separately rather than silently left out of the page counts.
Do you store my scan results?
Results exist for the length of your scan session in your browser. There is no account and no dashboard of past scans.
Can I use this on a very large site?
Sitemap parsing handles sitemap indexes with many child sitemaps, and scans run through a small concurrent queue so large sites do not overwhelm the API or this service. Very large sites may hit the per-scan URL cap; the preview before scanning tells you if that happened.