container audit
GTM-58Z9BNQ
37 tags, 5 custom scripts, 6 third-party hosts — an ordinary container, near the middle of what we measure (median: 39 tags, 4 custom scripts).
- 5 custom HTML tags carrying 3 KB of JavaScript. This runs on every page the container loads on.
- 6 third-party hosts reachable from its tags.
Tags37
Custom scripts5
Third parties6
Delivered520 KB
Versions71
What we observed
A real browser loaded beeldengeluid.nl a month ago and recorded every request it made. This is what happened, as distinct from what the container is configured to do. It is one page load — anything that fires only deeper in the site did not fire here.
Container loaded from
googletagmanager.com — GoogleMeasurement sent to
google-analytics.com — GoogleConsent
OneTrust answered its own API. 4 measurement hits left the page before it was granted, carrying a client id (whether that is permitted depends on jurisdiction, and this was not a European visit). 1 host appeared only after consent was granted. Google recorded
gcs=G101 (partial). 4 advertising hosts were contacted before anything was granted.Third parties contacted
24 hosts — use.typekit.net, www.googletagmanager.com, cdn.cookielaw.org, pagead2.googlesyndication.com, geolocation.onetrust.com, vimeo.com, cdn.sleak.chat, player.vimeo.com, and 16 more
dataLayer events seen
gtm.js, gtm.dom, gtm.load, gtm.scrollDepth, OneTrustLoaded, OptanonLoaded
Where the data goes
Not observed — on the page we loaded, measurement went to Google and nowhere else. observed on beeldengeluid.nl More info »
Findings
Ordered by consequence. review has a concrete cost when it bites; info is real but depends on your setup. Seen is how common it is across the containers we have measured — reported separately on purpose, because common and harmless are different claims.
reviewdocument.write (2)
2 pieces of custom code call document.write.
Whydocument.write blocks the HTML parser while it runs, and browsers ignore it entirely once the page has finished parsing — so an async-loaded tag using it can silently do nothing.
CheckIf these tags fire on page load they are costing render time; if they fire later they may not be working at all. Worth confirming the tag still does what it was added to do.
Seenseen in 18.4% of 46,522 containers measured
infoConsent configuration detected (3)
The container declares one or more consent signals.
WhyConsent handling is present in the container. This describes what the artifact declares; what actually happened on the page is measured separately, above.
CheckConfirm these settings match the consent policy you intend to enforce, and compare them with the before-and-after observation.
Seenseen in 44.6% of 46,522 containers measured
infoLoads JavaScript from another host (1)
1 piece of custom code fetch and run JavaScript from another host.
WhyWhatever that host serves executes with full access to the page — it can read the DOM, cookies and form fields. The code is not in this container, so it can change at any time without any change here.
CheckConfirm you recognise every host below and that someone owns the relationship. A host you cannot name is the one to chase.
Seenseen in 54.4% of 46,522 containers measured
infoUses browser storage (1)
1 piece of custom code read or write localStorage or sessionStorage.
WhyBrowser storage persists across visits and is not covered by cookie consent tooling, so it is easy to overlook when auditing what you keep on a visitor's device.
CheckConfirm nothing personal is being kept there, and that it is covered by your privacy notice.
Seenseen in 23.3% of 46,522 containers measured
Third parties it can reach
Each host is a party that can execute code or receive data in a visitor's browser. Follow one to see who else loads it. More info »
www.google-analytics.com ×12www.googleadservices.com ×7cdn.cookielaw.org ×2beeldengeluid.webpower.eu ×1cdn.sleak.chat ×1googleads.g.doubleclick.net ×1
What the custom templates can do
Custom templates are third-party code shipped inside the container. Injecting scripts and running page globals is ordinary for them — most tag templates need it to work — so this is an inventory, not a warning. It lists the capability each template declares so you can match it against templates you meant to install.
__cvt_7196303_209 private injects code from connect.facebook.net · runs page-level globalsDetected on
Sites observed loading this container. A container used across many hosts is a shared template; one on a single host is a bespoke build. Follow a site to see every container it loads.
What this audit describes
Containers change. These findings describe one specific artifact, and you can re-fetch it to check this reading.
| Container | GTM-58Z9BNQ |
|---|---|
| Published version | 71 — the identity of this configuration. It changes only when someone publishes. |
| Read at | 2026-08-12 22:16:54 UTC (a month ago) |
| Source | https://www.googletagmanager.com/gtm.js?id=GTM-58Z9BNQ |
| Body checksum | 609d64f13e5e98ebb770bd7f8cac9e97a561e01c019e7d17803e4d3b57c2388bEvidence of the exact bytes we read, not an identity: Google varies the response per request, so re-fetching an unchanged container yields a different checksum. Compare the published version instead. |
Re-audit
This reading is from a month ago. A container can be republished at any time, and nothing here updates on its own — a fresh read is the only way to know whether it still says this. Running it again replaces this page in place, so the link keeps working.
Put this container under version control. Tagora exports it to a repository you own, so every change arrives as a pull request. How it works »