Speed Tools A short update from Chrome addyosmani@

If JavaScript doesn’t bring users joy, thank it and throw it away.

The loading journey

“Get interactive before 1.3x the visually ready time”

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“Synthetic” “Real User Monitoring (RUM)”

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Proprietary + Confidential Proprietary + Confidential “Our Lighthouse score is 25!” Engineering Team

Proprietary + Confidential Proprietary + Confidential Hold the line: Performance Budgets Budget: ● 80KB/chunk ● 200KB total Result: ● Reduced Time to Interactive by 2 seconds Impact: ● Bounce Rate: 14% ● Average Duration: 31% ● Pages/session: 25% By setting a budget for tracking, and reporting build size deltas, we've prevented accidental changes that would have increased metrics like TTI, TTFMC and Time to First Tweet by over 100%. “ Paul Armstrong Web Developer, Twitter ”

Proprietary + Confidential Proprietary + Confidential Agree on a budget; then stick to it Project Timelines Proposal Discovery Design Development Launch Where we think performance happens Where we think performance happens Where performance needs to happen Proposal Discovery Design Development Launch Where we think performance happens Maintain performance budget Proposal Discovery Design Development Launch 1: 2: 3: Source: The Path to Performance by Katie Kovalcin

Proprietary + Confidential LightWallet

Proprietary + Confidential lighthousebot for CI 12 Bundlesize

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Proprietary + Confidential Proprietary + Confidential “We crossed the perf budget. ... Increase the budget!” We want to avoid this..

Proprietary + Confidential

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Confidential - Open questions - What can we do better?