posthog.com speed test — 20 Oct 2026

What these numbers mean

• The first byte arrived in 308 ms. That is workable, and the cheapest win left is caching or a warmer connection.
• The page transfers 2.35 MB over 26 request(s). Images files are 86% of it, so resize and recompress the largest images before anything else.
• The HTML itself arrives br-compressed.
• It runs over HTTP/3, so the assets share a connection instead of opening one each.
• 86% 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 1.26 s, inside the 2.5 s Google calls good.
• Layout stayed still (CLS 0.028), so nothing jumps under the reader's cursor.
• The main thread was blocked for 5.96 s, so taps and scrolling wait while scripts run.

Fix first: Image delivery and format - Serve WebP or AVIF with a JPEG fallback, size images to the space they occupy, and lazy-load anything below the fold. Images are usually more than half of a slow page.

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.