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.zip
MV3 · works in Chrome, Edge, Brave, Arc
// 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.

// 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.

Get a project key Or try the iframe demo