TagCheck
Open tag tester →
COMPARE TAGS

See what changed,
before it goes live.

Paste an original and updated tag to compare the QA signals that matter: trackers, click destinations, external scripts, VAST media, events, and macros.

Compare two tag versions

Use the complete HTML, JavaScript, VAST XML, or VAST URL from each version. Nothing is uploaded or retained.

◇ Comparison happens locally. Full tag code and complete URLs are not included in the results.