Local-only performance profiler

Catch memory leaks & UX regressions in any web app

Perf Recorder records memory, CPU, DOM growth, Core Web Vitals, network and console data straight from your browser tab, then charts it so a leak or a slowdown is obvious at a glance.

100% local, nothing uploaded No account, no servers Works on any site
possible leak
app.example.com/blotters
Mem / min
7.4 MB
INP
248 ms
DOM / min
96
JS heap, climbing over 40 cycles
Everything in one recording

The signals that actually explain a slow web app

One Stop button captures a complete, timestamped picture of the tab, with no instrumentation in your code.

Memory-leak detection

Tracks JS heap, RSS and DOM growth, then flags a possible leak when usage trends up across the run instead of settling.

CPU & main-thread

Per-tab CPU usage plus main-thread busy time from long tasks, so you see exactly when the page locks up.

DOM & listeners

Node counts (top frame & Blink) and JS event-listener totals over time. The usual suspects behind a creeping leak.

Core Web Vitals

INP, CLS, LCP, FCP and Long Animation Frames sampled live, so responsiveness regressions show up next to the cause.

Network & WebSockets

Request counts and WebSocket frames are captured alongside everything else, so traffic spikes line up with the metrics.

Console & errors

Console output and errors are recorded with timestamps and surfaced in the report, with no DevTools left open.

Three steps

Record, stop, analyze

No setup in your app. Profile a real user flow (a soak test, a noisy dashboard, a long session) and read the result here.

Record

Open the extension on the tab you want to profile and hit Record. It samples the page every few seconds in the background.

Stop

When your flow is done, press Stop. A perf-report-*.json file is saved straight to your Downloads. Nothing leaves your machine.

Analyze

Drop that file into the analyzer to chart every metric, see the leak verdict, and pinpoint regressions.

Private by design

Your data never leaves your browser

Recording and analysis happen entirely on your device. There are no servers, no analytics, and no accounts. Reports are saved only to your computer, and the analyzer reads them locally too.