Measure page speed

Page speed is on for every site. The emberbee script you already have measures it, so there is nothing to add.

Numbers show up under Speed on your site's dashboard as visitors load your pages.

Open your site's Settings and switch off Measure page speed. Within a minute, visitors stop loading the extra code that measures speed. The numbers already measured stay on the Speed page, and you can switch it back on any time.

Each number is the 75th percentile: three in four visits were at least this fast. Google uses the same thresholds to rate a page.

• Largest Contentful Paint (LCP) is how long the main content, such as the hero image or the headline, takes to appear. Good is 2.5 seconds or less. Poor is over 4 seconds.
• Interaction to Next Paint (INP) is how long the page takes to respond when someone clicks, taps, or types. Good is 200 ms or less. Poor is over 500 ms.
• Cumulative Layout Shift (CLS) is how much the page jumps around while it loads, such as text moving when an image or ad appears above it. Good is 0.1 or less. Poor is over 0.25.

Two more numbers help explain a slow LCP. First Contentful Paint (FCP) is when anything first appears. Time to First Byte (TTFB) is how long your server takes to start answering.

Every number splits by page, device, country, and browser, so you can compare mobile with desktop.

A client-side route change, such as a Link click in Next.js, starts a new measurement for the new page. INP and CLS count toward the page where they happened, not the page the visitor first loaded.

Browsers report LCP, FCP, and TTFB only for a full page load. A page reached by a route change shows INP and CLS only.

Not every browser reports every number. As of October 25, 2026, MDN's browser compatibility data (version 8.1.7) lists:

• LCP in Chrome 77, Edge 79, Firefox 122, and Safari 26.2 and later.
• INP in Chrome 96, Edge 96, Firefox 144, and Safari 26.2 and later.
• CLS in Chrome 77 and Edge 79 and later, and other Chromium browsers. Firefox and Safari don't report it.

So CLS comes only from Chromium visitors, and older Firefox and Safari versions send no LCP or INP. If most of your visitors use Safari on iPhone, filter by browser to see which numbers you have.

Page speed is included in every plan. Speed measurements don't count toward your monthly event allowance, and they set no cookies, just like the rest of emberbee.