Check library · Speed and Core Web Vitals
Very large JavaScript payload
Why it matters
Parse and execution time on mid-range phones is where most performance is lost.
What to do about it
Code-split, defer what is not needed for first paint, drop unused libraries.
This one is reported rather than applied. It needs a judgement a person has to make, and applying it automatically would be a change to your site that nobody decided on.
How it is weighted
These are the values the scoring actually uses, not a description of them. Priority is derived from all three rather than chosen, which is why a high-impact, low-effort finding surfaces above a severe one that would take a quarter to fix.
- Severity
- medium
- Impact
- 40% of the weight this category can carry
- Effort
- 70%, where 100% is a project rather than a change
- Confidence
- 80% that a hit is a real problem rather than a pattern we misread
- Area
- Speed and Core Web Vitals
Other checks in Speed and Core Web Vitals
highServer response is slowslow_responseneeds a decisionmediumPage weight is largeheavy_pageneeds a decisionmediumRender-blocking stylesheets and scriptsrender_blocking_resourcesneeds a decisionlowImage uses a legacy formatimage_legacy_formatfix writtenlowImage has no width and heightimage_no_dimensionsfix writtenlowBelow-the-fold images load eagerlyimage_no_lazy_loadingfix written
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