openlibrary.org speed test — 20 Oct 2026

What these numbers mean

• The first byte arrived in 405 ms. That is workable, and the cheapest win left is caching or a warmer connection.
• The page transfers 153.0 KB over 26 request(s). Images files are 91% of it, so resize and recompress the largest images before anything else.
• The HTML itself arrives gzip-compressed.
• It runs over HTTP/3, so the assets share a connection instead of opening one each.
• 54% of the weight comes from other hosts (analytics, fonts, embeds), which also means their slow day becomes your slow day.
• The largest element painted at 756 ms, inside the 2.5 s Google calls good.
• Layout shift is 0.104 (good is under 0.1): something without a reserved size is loading late - an image, an ad, or a font swap.
• The main thread was blocked for 127 ms in total, which is not enough to feel.

Fix first: Server response time (TTFB) - Cut server think time: page cache, query indexes, fewer synchronous calls to third parties inside the request. Connection setup is distance, so a nearer region or a CDN edge helps instead.

Read on one shared server, not a visitor's phone: use it to compare pages against each other, not as a promise about every connection. We fix what these tests find.