URL Query String Diff

How to use

1. 1Paste a URL into URL A and a second URL into URL B. Schemes are optional, https is filled in when missing.
2. 2Read the parameter summary tiles for at-a-glance counts of Same, Changed, Only in A, and Only in B parameters.
3. 3Scan the structural diff table to spot scheme, host, port, path, or fragment changes that are easy to overlook in long URLs.
4. 4Use the filter strip to switch between Show all, Differences only, and Same only when you want to zoom in.
5. 5Tune the options: case-insensitive keys, set-match for repeated values, decode for human-readable text, or ignore fragment.
6. 6Click Swap A and B to reverse the sides, Clear both to start over, or Copy diff summary to share a plain-text report.

About this tool

URL Query String Diff compares two URLs and reports every difference between them so you can answer questions like 'which UTM tags changed between these two campaign links', 'why does this staging URL behave differently from production', or 'which tracking parameters did the cleaner actually strip'. Paste a URL into A and another URL into B, optionally with no scheme (the tool defaults to https), and the result panels update live. The parameter table walks every key in the order it first appears across A and B, classifies it as Same (key present on both sides with matching values), Changed (key present on both sides with different values), Only in A (key removed from B), or Only in B (key added in B), and shows the full value list per side so repeated keys like ?tag=red&tag=blue are visible. The structural diff section compares scheme (http vs https), host (api.example.com vs staging.api.example.com), port, path, and the URL fragment (#section) so a host swap or a hash change is impossible to miss. Options tune the comparison: case-insensitive keys folds UTM_SOURCE and utm_source together, set-match treats ?tag=red&tag=blue as equal to ?tag=blue&tag=red while ordered match keeps the appearance order significant, decode values shows the percent-decoded form for human reading, and ignore #fragment skips the hash row when the fragment is noise. A filter strip flips between Show all, Differences only, and Same only so you can zoom in on the rows that changed. Five worked samples cover the most common comparison jobs: UTM campaigns side by side, pagination drift across API calls, repeated keys with multiple tag values, staging vs production environment URLs, and an original tracker-laden link versus a cleaned share link. Copy diff summary returns a plain-text report ready to paste into a ticket, Slack thread, or pull request review. Parsing uses the native URL constructor and URLSearchParams, both standard browser APIs, so the URLs you compare stay on your device. Useful for SEO and growth teams auditing campaign URL conventions, QA engineers spotting regressions between feature branches and main, marketers verifying that a URL cleaner removed exactly the parameters expected, developers comparing API requests captured from logs, and content auditors deduplicating the canonical from tracking variants.

Free to use. Works in your browser. No signup, no login.