Performance budget report

The same property-listings page, built twice. Identical markup and copy; different load behaviour. Measured with Lighthouse on an emulated mid-tier mobile device over 4G, median of 3 runs.

20
Legacy build Poor
100
Remediated build Good

All gating budgets met. The legacy build breaches 7 of 7 budgets and would fail the pipeline; the remediated build passes every one. Only the remediated build gates — the legacy build is kept as a fixture so the budgets are proven capable of failing.

Before and after

Each bar is scaled to the worse of the two values, so the gap is the point rather than the absolute width. The final column is the reduction.

Metric Legacy build Remediated build Change
Largest Contentful Paint budget ≤ 2,500 ms
9,243 ms
906 ms 		−90%
First Contentful Paint budget ≤ 1,800 ms
8,952 ms
756 ms 		−92%
Speed Index budget ≤ 3,400 ms
8,952 ms
756 ms 		−92%
Total Blocking Time budget ≤ 200 ms
1,947 ms
0 ms 		−100%
Cumulative Layout Shift budget ≤ 0.100
0.197
0.000 		−100%
Total transfer size budget ≤ 391 KB
880 KB
11 KB 		−99%

Legacy build vs budget

Not gating — kept to prove the budgets can fail.

MetricMeasuredBudgetStatus
Performance score 20 ≥ 90 Breached
Largest Contentful Paint 9,243 ms ≤ 2,500 ms Breached
Total Blocking Time 1,947 ms ≤ 200 ms Breached
Cumulative Layout Shift 0.197 ≤ 0.100 Breached
First Contentful Paint 8,952 ms ≤ 1,800 ms Breached
Speed Index 8,952 ms ≤ 3,400 ms Breached
Total transfer size 880 KB ≤ 391 KB Breached

Remediated build vs budget

This is the gate. A breach here fails the build.

MetricMeasuredBudgetStatus
Performance score 100 ≥ 90 Within budget
Largest Contentful Paint 906 ms ≤ 2,500 ms Within budget
Total Blocking Time 0 ms ≤ 200 ms Within budget
Cumulative Layout Shift 0.000 ≤ 0.100 Within budget
First Contentful Paint 756 ms ≤ 1,800 ms Within budget
Speed Index 756 ms ≤ 3,400 ms Within budget
Total transfer size 11 KB ≤ 391 KB Within budget

What Lighthouse suggested fixing

The top opportunities reported on the legacy build, largest saving first. These are what turn a red budget into a task list.

OpportunityTime savedBytes saved
Minify JavaScript 600 ms 115 KB

Generated from report/data/summary.json. Timings are the median of 3 runs; a single Lighthouse run varies enough that a budget built on one sample is a coin toss.