pulse_
// chrome extension

Pulse DevTools

A Chrome extension that captures Web Vitals, network calls, resources, and JS errors from any tab — including localhost, private IPs, and corporate VPN apps the iframe demo can't reach. Per-tab record button. No code changes to the target site.

pulse-extension.zipWhat's new
MV3 · works in Chrome, Edge, Brave, Arc
Checking for installed extension…
// install
  1. 1
    Unzip the download
    You'll get a folder named pulse-extension.
  2. 2
    Open chrome://extensions
    Or your browser's equivalent — edge://extensions, brave://extensions.
  3. 3
    Enable Developer mode
    Toggle in the top-right corner of the extensions page.
  4. 4
    Click 'Load unpacked'
    Select the unzipped pulse-extension folder. The pulse_ icon appears in your toolbar.
// use
1. Paste your project key

Open the popup, paste your pk_… key from the dashboard, click Save.

2. Start capture per tab

Navigate to the app you want to measure and click Start. The tab reloads instrumented.

3. Watch the live counter

Events stream into your dashboard — open the session for the full breakdown.

// why an extension?

Public web pages can't iframe internal apps (Chrome's Private Network Access blocks it) and can't read cross-origin Web Vitals. The extension runs same-origin inside the tab itself, so it sees the same signals as the SDK snippet — without needing to modify the target site.

// companion · pulse recorder

Record & replay UI journeys

v1.0.0

A second, standalone extension that lets a tester click through a journey once and replay it on demand. Pair it with Pulse DevTools and every replay produces a clean, comparable performance benchmark — no human needed in the loop.

  • NEW · Full-tab UI (v1.0.0): the cramped toolbar popup is gone. Clicking the Pulse Recorder icon opens a full browser tab with proper Recorder, Concurrent suite, and Settings tabs — pick any open tab as the recording target, switch between recording and load-testing without losing context, and never have the popup auto-dismiss in the middle of a click.
  • Concurrent Suite Mode (v0.8): queue up to 20 tabs in parallel from one popup click — pick scripts, set iterations + stagger + concurrency, and a live job grid streams pass/fail per tab. Each tab is an isolated session: separate cookies, storage, and replay state.
  • Auto-capture with Pulse DevTools (v0.9): tick one box in the Suite modal and every spawned tab is instrumented by Pulse DevTools via cross-extension RPC — 20 tabs = 20 benchmark sessions auto-flushed to your dashboard, ready for Root Cause + AI Consultant rollups.
  • Record-first workflow (v0.9.1): the Concurrent suite tab keeps its picker visibly empty (with a "Record one first" hint) until you have a saved script — the flow stays linear: Start recording → Save script → Run suite.
  • Rich input capture: click, input, change, submit, scroll, Enter/Tab/Esc with a multi-strategy selector cascade (testid → ARIA role+name → id → text → CSS path).
  • Map & canvas gestures (5a): pointer-drag (downsampled waypoints) and mouse-wheel zoom captured with region-relative coordinates — works on Google Maps, Leaflet, canvases and SVG.
  • Shadow DOM & HTML5 drag-and-drop (5b): selectors walk shadow roots via composedPath(); native dragstart/drop with dataTransfer are recorded and replayed end-to-end (kanban boards, file-drop zones, Lightning components).
  • Network-idle waits & assertions (5c): replay monkey-patches fetch/XHR to wait for in-flight requests between steps; Alt+click during recording captures text-contains / visible / value-equals assertions that fail the run with a clear message.
  • Privacy: passwords and obvious card/CVV fields are auto-redacted to <<SECRET:…>> placeholders.
  • Deterministic timing: replay reuses recorded pacing so LCP/CLS/INP reflect human-like timing.
  • Portable: export/import scripts as JSON — diffable in PRs and synced to your dashboard via project public key.
Load it the same way as Pulse DevTools — chrome://extensions → Developer mode → Load unpacked.
// what you get in the dashboard
Replayable timeline

Scrub through APIs, WS frames, long tasks and vitals on one cursor — inside the APIs and Websockets tabs.

WS hotspots

Per-channel chatty / heavy / blocking / bursty stats with a ±2.5s context window for the worst frame.

Hardware Impact

Device class buckets so a slow device doesn't get blamed for slow code (only the extension reports CPU/GPU/Memory).

Root Cause & Compare

Diff two sessions side-by-side or correlate project-wide regressions to deploys, devices, network or geography.

// release notes
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Get a project key Or try the iframe demo