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JavaScriptbundle size
The total amount of JavaScript a visitor must download, parse and run for a page.
Growth Score · Activation
Definition
What it means
Every kilobyte of JavaScript costs more than an image of the same size because it must also be executed. Large bundles slow phones the most.
Removing unused libraries and splitting code gives quick wins.
In Growth Score
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Guides that cover it
Checkout audit: 12 leaksTwelve places a sale leaks, in cost order, with a test and a fix for each one.When to redesign your siteHow to tell a real redesign need from vanity, and how to do it without losing rankings.Fast for real visitorsRead real visits, then fix images, scripts, layout shifts and the slow start.
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FAQ
Quick answers
What is JavaScript bundle size?
The total amount of JavaScript a visitor must download, parse and run for a page.
Where does it sit in Growth Score?
It belongs to the Activation pillar, one of the 12 pillars your score is built from.
What should I read next?
Start with Code splitting and Main thread, then browse the other terms in Activation.
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Growth Score reads your site and scores its Activation pillar against sites like yours.
Your Growth Score is 100
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