Google replaced First Input Delay with Interaction to Next Paint (INP) as a Core Web Vital, and a lot of stores that passed the old test now fail the new one. INP measures how quickly the page responds when a customer actually clicks or types, across the whole visit, not just the first interaction. For an online store, that is the “add to cart” button, the filters, the checkout fields.
Why it matters beyond rankings
Rankings are the smaller part. The bigger part is that a slow response after a click is read by customers as “did that work?”, followed by a second click, a duplicate cart item, or leaving. Stores that fix INP see the effect in conversion before they see it in search.
Where the time goes
- Third-party scripts. Chat widgets, analytics, marketing pixels, A/B testing tools. Each one runs on the main thread, exactly when the customer wants to interact.
- Heavy JavaScript frameworks loaded for everything, including pages that are mostly text.
- Unoptimised images and fonts that block rendering and shift the layout.
- Slow server responses on the pages that matter: category pages with large catalogues and filters, cart updates, search.
What we do in a performance project
- Measure with real-user data (Chrome UX Report, Search Console) and lab tools, on the pages that earn money.
- Remove or defer third-party scripts; load the rest only after consent and only where needed.
- Fix the server side: PHP version, opcode cache, database indexes, query caching, image delivery, CDN.
- Trim the front end: modern image formats, self-hosted fonts, less JavaScript, no layout shifts.
- Re-measure and report the before/after numbers, then set up monitoring so it does not regress after the next plugin install.
A quick self-test
Open Search Console, go to Core Web Vitals, and look at the mobile report. If your product and category pages are “poor” or “needs improvement”, you are losing orders today. Speed and performance optimisation is one of our standard services; send us the URL and we will tell you what is slow and what it would take to fix.
