Main issue: The Shopify theme “Interactivity” metric is steadily increasing day-by-day despite no code or theme-editor changes. The store’s Google PageSpeed results show strong FID (First Input Delay) and INP (Interaction to Next Paint) on both mobile and desktop, creating a discrepancy.
Context and possible causes:
FID was dropped as a Core Web Vital in March 2024 and replaced by INP. The Shopify dashboard may still reference or compute an outdated/buggy metric, inflating averages over time.
Potential (but less likely) interference from third‑party “optimization” code that skews offsite test results.
Inconsistencies noted: other objectively slower stores show a much lower Shopify interactivity value (e.g., 35 ms).
Recommendations proposed:
Roll back recent changes and A/B test to isolate any regression.
Audit for any performance “optimization” scripts that could affect measurements.
Ask Shopify directly via the Shopify Partners Slack channel for clarification on how “Interactivity” is currently calculated.
Status: Unresolved. No concrete fix yet; key open question is whether Shopify’s “Interactivity” metric is accurate/current (FID vs. INP). A screenshot is provided and is central to understanding the reported rise.
Summarized with AI on December 30.
AI used: gpt-5.
I have a performance issue with Interactivity on the client Store.
The major problem is that this number keeps increasing daily (without changing the code) or modifying the Theme(Theme editor).
When I click interactivity to see reports in Says FID(First input Delay) , my understanding is that interactivity == First input delay, When I’m checking the website in Google PageSpeed first input delay in perfect on both desktop and mobile …
Can someone please explain what the problem is and how I can fix it?
If the number keeps going up and IF shopify is using that under the hood this could indicate the dashboard JUST hasn’t been updated so is measuring a metric that returns an amount that is increasing the average.
Aside: if you paid for some “performance optimization” service and speed reports by a third party web service always return good there’s always a chance you got scam code messing with the offsite reports you see that just detects when that site tries to load your website.
Based on PageSpeed (Google), both FID and INP are good (Mobile/Desktop).
It’s all my code and it’s as clean as possible. I can say that it’s one of the fastest websites I’m working on.
I have other stores where the actual performance (from users’ perspective) is significantly slower, and Shopify gives them a 35ms interactivity score.
I agree, Tim. What matters for ranking is Google, and the “actual speed” real user experience, they are good. But this number has doubled in a week and increases every day, which is scary. What if this metric really means something?
