What happened?
Every event is captured the moment it fires, from dataLayer.push, SDK calls like gtag() and fbq(), and the network itself. Two capture channels run in parallel, so early pixels aren't missed.
A magnifier for tracking events.
See what your page really sends.
Eventloupe is a Chrome DevTools extension. It shows every pixel, tag and dataLayer push a page fires, what was sent, and what was actually observed.
Chrome extension, launching soon on the Chrome Web Store.
Share feedback on GitHubIllustrative example of one add-to-cart click on a sample page. Move the loupe, or tap and drag it.
- Example of what Eventloupe reports on a sample product page.
- Page view: Google Tag Manager container loaded, status 200. GA4 view_item observed, status 204. dataLayer view_item push seen. Meta Pixel ViewContent observed, status 200.
- Add to cart click: GA4 add_to_cart observed, status 204. Meta Pixel AddToCart observed, status 200. TikTok AddToCart unknown, no response could be observed.
- Consent banner: Consent Mode ad_storage observed as denied. Google Ads conversion failed, status 500.
How it works
Three questions, answered for every event.
Most tag debuggers tell you a request was made. Eventloupe tells you what happened to it, and why it says so.
How do we know?
Each event is traced through six stages, from your app to the response. Every stage is marked observed, failed, or unknown, so you can see exactly where the evidence stops.
What should be fixed?
Rule-based diagnostics with stable codes, EL1000 to EL9999. The same input always gives the same answer. No AI decides what's valid.
The truth gap
Evidence, not guesses.
Fired is not the same as delivered. A missing response isn't a success, and it isn't a failure. Eventloupe keeps "I couldn't observe this" as its own answer instead of rounding it to yes or no.
Observed
httpStatus: 204
The request was seen and the response came back clean.
Failed
httpStatus: 500
The request was seen and delivery was confirmed to have failed.
Unknown
httpStatus: null
Not observable from the browser. Shown as unknown, never as an error you didn't see.
Standard debuggers vs. Eventloupe
| Capability | Standard debuggers | Eventloupe |
|---|---|---|
| Status model | Success or fail. Two states. | Observed, failed or unknown. Three states. |
| What it relies on | Typically the SDK's own report of what it did | The network request and its response, alongside the SDK call |
| Missing evidence | Has to be shown as a pass or a fail | Shown as unknown, never guessed |
| Delivery | Not verified | Response status recorded where the browser exposes it |
| The report | A pass/fail badge | An evidence trail: six stages, each marked observed, failed or unknown |
"Standard debuggers" describes the common pass/fail approach, not any specific product.
Same event, two answers
Standard debugger
purchaseSuccess
The SDK call fired, so a pass/fail badge says it worked.
Eventloupe
- ✓Application
- ✓Tag Manager
- ✓SDK
- ✓Network
- ✗Response
Failed at ResponseHTTP 500 · EL1003
The request left the browser. The server's response says it wasn't recorded.
Illustrative example.
The life of one event
Six stages, each marked observed, failed or unknown. Select a stage to see what Eventloupe looks at there.
Stage 1 of 6 · Application
- What it looks at
- The page's own call: a
dataLayer.push, or an SDK call likegtag()orfbq(). - Evidence recorded
- The event name and payload exactly as the page produced them.
- Unknown when
- The call ran before Eventloupe could hook it. The network stage may still catch the request.
Illustrative pipeline for a single event. Failed stages are flagged where the evidence is, and unknown stages stay unknown.
Who it's for
Built for the precision-obsessed.
01 · Developers
Verify dataLayer pushes and SDK invocations without guessing.
dataLayer.push → gtag() → request
02 · Analysts
Cross-reference GA4 and Meta Pixel events in one unified timeline.
GA4 + Meta Pixel · one timeline
03 · Marketers
Confirm conversion requests were sent and got a response, not just fired.
request sent · response observed
Diagnostics
Every finding has a code.
Codes are permanent identifiers: the wording can improve, the code never changes. They come from fixed rules, so the same input always gives the same result.
EL1001Medium
Network request not observed
The JS API call was intercepted, but no matching network request was seen.
FixCheck whether a consent manager or ad blocker is suppressing the request.
EL1002Critical
HTTP 4xx client error
The tracking server rejected the request, so the event was lost.
FixCheck the payload for malformed parameters or an invalid pixel ID.
EL1003Critical
HTTP 5xx server error
The tracking server returned an error, so the platform failed to record the event.
FixThis is platform-side. Retry, or check the platform's status.
EL2003High
Event ID mismatch
The event_id in the JS call doesn't match the one in the network request.
FixPass the same event_id to fbq() and to the CAPI server call.
EL4002Medium
ad_storage denied on a conversion
The conversion may not be attributed to the right ad click.
FixMake sure Consent Mode is configured correctly for your consent platform.
EL4012Critical
Consent default set after config
gtag("consent","default") fired after gtag("config"), so tags may have fired with the wrong consent state.
FixMove the consent default before any config call, ahead of your tag manager.
Eventloupe reports what it observed. A request it doesn't see is "not observed", and the fixes suggest likely causes without claiming one. See how codes are grouped in the docs →
The panel
One panel inside DevTools.
Captured from real sites, not mock-ups. Add to cart, checkout and consent, across every platform at once.
Coverage
21 platforms. One timeline.
Eventloupe replaces switching between a handful of single-purpose debuggers. Every platform is read the same way and validated against its own documentation.
- dataLayer
- Google Analytics 4
- Google Tag Manager
- Meta Pixel
- TikTok Pixel
- Google Ads
- Snapchat Pixel
- Pinterest Tag
- LinkedIn Insight
- Reddit Pixel
- Segment
- Adobe Analytics
- Amplitude
- Mixpanel
- Microsoft UET
- X Pixel
- Criteo
- Floodlight / CM360
- Taboola
- Outbrain
- Quora Pixel
All product names are trademarks of their respective owners. Eventloupe is an independent tool and isn't affiliated with or endorsed by any of them.
Privacy
It all stays in your browser.
Eventloupe doesn't collect, transmit or store any data outside your browser.
Accounts
None needed
Servers
None used
Analytics inside
None
Data lives
In your browser
This site practises the same thing. It loads no trackers, no third-party fonts and no analytics. Open Eventloupe on this page and see for yourself.
Read the full privacy policy →Launching soon
Coming to the Chrome Web Store.
Eventloupe is built for developers, analysts and marketers who need to know what a page really sent. Questions or feedback are welcome.
A magnifier for tracking events.