perf-lab

Everyone measures. Nobody simulates.

Drop in a Lighthouse report and start switching things off. Turns “that library will hurt performance” into “that library costs 0.4 s of LCP and 7 points”. Nothing is uploaded — the report is parsed in your tab.

Drop a Lighthouse JSON report here

DevTools ▸ Lighthouse ▸ run it ▸ the ⋮ menu ▸ Save as JSON. A PageSpeed Insights or CI report works too — same schema.