Change forensics

When tracking breaks, find the cause in seconds.

A Facebook Pixel silently disappears. A GA4 tag stops firing. A consent banner regresses. Without Tracefox, someone has to notice, then dig through Chrome DevTools + Git history + Shopify changelog + two Slack channels to figure out what happened. Tracefox tells you in one screen.

The problem

Broken tracking is hard to detect. Harder to explain.

Tracking code isn't like a broken checkout, there's no 500 error, no user complaint, no failed health check. The page still loads. Conversions just stop being attributed. By the time someone notices, you've lost weeks of attribution data and the site has been through ten deploys.

Silent failure

Missing Pixels don't throw errors. The client keeps spending on Meta ads with no conversion data flowing back for weeks.

No changelog

When tracking breaks, nobody remembers what changed. Theme update? New app? Developer patch? Without evidence, it's guesswork.

Costly to fix late

Detected on day 1: 10-minute fix. Detected on day 30: weeks of lost data, angry client, emergency debug session.

How Tracefox finds the cause

Every change is captured with timestamped evidence

Tracefox runs a real headless browser against every monitored site on a schedule. Each scan is stored as a snapshot. When something changes, the diff engine extracts the before/after, so you never have to guess what the page looked like last Tuesday.

01

Timestamped snapshots

Every scan becomes an immutable snapshot. When you ask 'what did the page look like on April 14?', Tracefox shows you, scripts, cookies, DOM, screenshot.

02

Diff with before/after

Each detected change includes the previous value and the new value. 'Pixel ID 123456 was present, now missing', not 'something changed.'

03

Narrowed to a window

If a scan on Monday shows the Pixel present and Tuesday's shows it gone, you know the break happened in that 24-hour window. Now you can check deploys.

04

Categorized automatically

Each change is tagged: tracker removed, cookie added, consent banner broken, policy updated. You filter by what matters, not by raw diff noise.

05

Explained in plain English

Instead of 'fbq function not found in document.head', Tracefox writes 'Facebook Pixel has been removed from the page, this breaks Meta ads tracking.'

06

Severity ranked

HIGH severity fires an alert within minutes. LOW events roll up into the weekly digest. You never wake up to a false alarm.

Real example

A missing Facebook Pixel, solved in three clicks

Here's what the debugging flow actually looks like with Tracefox.

1

Alert fires

9:03 AM. Slack ping. 'HIGH severity on acme-store.com: Facebook Pixel removed.' Link to the detection page.

2

Open the detection

You see the before/after. Previous scan (Apr 13, 9:01 PM): fbq('init', '1234567890') present in <head>. Latest scan (Apr 14, 9:01 AM): fbq not found.

3

Narrow the window

Break happened in a 12-hour window. You check the client's Shopify admin, theme was updated at 2:40 AM by their overnight developer.

4

Fix + verify

Developer reinstates the Pixel. Next scheduled scan (10:01 AM) confirms it's back. Tracefox updates the detection to 'resolved' automatically.

HIGH · acme-store.com2m ago
Detection type
Tracker removed
Plain explanation
The Facebook Pixel (Meta) was loading on this page yesterday but is no longer present. This means Meta ads conversion tracking is currently broken for this site.
Before
fbq('init', '1234567890')
After
, not found.
Window: Apr 13 21:01. Apr 14 09:01 UTC (12h)
What Tracefox watches

Any tracker, pixel, cookie, or consent change

If it loads on the page or gets set in the browser, Tracefox tracks it. Root-cause analysis works for any of these, not just the big three.

Ad pixels

Meta (Facebook), Google Ads, TikTok, LinkedIn, Twitter/X, Reddit, Pinterest, Snapchat.

Analytics

Google Analytics (UA + GA4), Hotjar, Mixpanel, Amplitude, Plausible, Fathom, Matomo.

Cookies

Every cookie set after page load + consent, categorized by vendor and purpose.

Consent banners

OneTrust, Cookiebot, Osano, Iubenda, Termly, Complianz, CookieYes + custom CMPs.

Policy pages

Privacy and cookie policy URLs are scanned for material content changes.

Custom patterns

Match any script src or global variable, catch internal-only tags and heatmap tools.

Manual debugging vs Tracefox

Without Tracefox

  • Notice attribution dropped (if you notice)
  • Open Chrome DevTools, check Network tab
  • Ask developer when they last deployed
  • Dig through Git history on the theme repo
  • Check Shopify app changelog
  • Post in client Slack asking who did what
  • Eventually reinstall the Pixel by hand
  • ~4 hours, days of lost data

With Tracefox

  • Slack alert within an hour of the break
  • Open the detection page, see before/after
  • 12-hour window narrows it to one deploy
  • Reinstall the Pixel
  • Next scan confirms resolved, automatically
  • ~10 minutes, minutes of lost data

Stop finding broken tracking in arrears.

Tracefox watches every client site, flags the changes that break tracking, and gives you the evidence to fix them in minutes. Free for one website, forever.