How to use

1 Install from the Chrome Web Store

Open the listing and click Add to Chrome:

Shadow Monitor on Chrome Web Store

Pin the extension from the puzzle-piece menu so the toolbar icon is easy to reach.

2 Add your UAT domain

Click the extension icon → open Settings (gear). Under UAT environments, read the disclosure, check I understand…, then type the hostname only (no https://, no path):

uat.example.com

Include the port when it is not 443, e.g. localhost:3000.

Grant every host you will use in the session — for example both a public UAT site and a separate CMS/Admin host. Capture is per origin pattern; a single grant does not cover other subdomains. After adding an origin, hard-reload that tab so scripts attach from the start.

Same-tab redirects between two granted origins (Admin → live site) stay in one recording; Download includes both in the rolling window. Network and console are also captured inside same-origin iframes (common in CMS admin UIs); DOM replay remains the top document.

Leave Capture / Downloads / Encryption at their defaults unless you need something special.

3 Hard-reload the UAT tab

Open your UAT site and hard-reload once so capture scripts load from the start of the page:

• Mac: Cmd+Shift+R
• Windows / Linux: Ctrl+Shift+R

4 Reproduce and download

1. Click the Shadow Monitor icon — status should show recording.
2. Reproduce the bug as usual.
3. Optionally describe what went wrong in the popup.
4. Pick an export range (e.g. last 10 min or all) and click Download.

You get a uat-report-*.json.gz file in Downloads (or the folder you chose in Settings). Nothing is uploaded — the file stays on your machine until you share it.

What “last N minutes” means

Download last N minutes is a wall-clock lookback on the tab where you open the popup — not “N minutes of continuous DOM playback.” Capture soft-pauses about 3 seconds after you leave that tab (other tabs, another window). While paused, no DOM / network / console events are written. Coming back resumes with a fresh full snapshot.

Example — you click Download last 5 min at 12:10:

• 12:00–12:02 — work on the UAT tab (recorded)
• 12:02–12:08 — other tabs (paused after ~3s; almost nothing written)
• 12:08–12:10 — back on UAT (recorded)

The export window is 12:05–12:10 on the clock. The first UAT stretch (12:00–12:02) is already outside that window. Inside the window you mainly get the ~2 minutes of activity from 12:08–12:10 — not five minutes of replay.

The popup shows recording time (active, un-paused) separately from buffer span (oldest→newest event timestamps). Prefer staying on the UAT tab while reproducing, and open Download on that same tab. Settings → Keep last is the rolling retention cap; a download range cannot exceed it.

5 Open the replay viewer

From the popup, click Open replay viewer, or open viewer/viewer.html from the extension package. Drop the .json.gz file onto the page to replay DOM, network, console, and storage.

Tips

• Each tab records in parallel. Download from the popup on the tab you care about.
• Background tabs soft-pause — see What “last N minutes” means if a download looks shorter than expected.
• Passwords, payment fields, and .uat-mask / data-uat-mask stay masked in DOM replay.
• Turn off Record input values or Capture cookies in Settings if you need a tighter buffer.
• Optional encryption (buffer on disk or encrypt-for-sharing) is in Settings — there is no passphrase recovery.