GTM Diff
Load a "before" and "after" container export to see exactly what changed. Click any modified, added, or removed element to view a visual diff or a line-level JSON diff.
Free, no account required.
Drop GTM JSON export or click to browse
Drop GTM JSON export or click to browse
Load both containers above to see the diff.
How it works
Export both versions
In GTM, open Admin then Export Container. Do this once for the older version and once for the newer one.
Load Before and After
Drop each JSON export into its panel, or click to browse. Everything runs in your browser, nothing is uploaded.
Review the diff
Every added, removed, or modified tag, trigger, and variable is listed immediately. Click any row for the full detail.
What you can check
Added, removed, and modified elements
Tags, triggers, and variables are matched by ID, with a name-based fallback for elements that were deleted and recreated.
Field-level changes
See exactly which properties changed on a modified element: firing triggers, parameters, conditions, and more.
Visual and JSON diff
Switch between a readable summary of what changed and a line-by-line JSON diff for any element.
Filter by status
Show only added, removed, or modified elements, or view everything at once.
Export the results
Download the full diff as CSV or JSON to share or keep as a record.
