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URL Query Parameter Diff

Compare decoded query parameters from two URLs, preserving duplicate-value order and distinguishing missing keys from empty values.

Two absolute HTTP/HTTPS URLs

Complete JSON query comparison

Browser only

Runs locally in your browser. Your files, pasted content and generated output are not uploaded. Reset clears this tool’s working data.

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How to use this tool

  • Enter Before URL and After URL.
  • Select Compare query parameters.
  • Download query-diff.json for every decoded key, ordered before/after values and change kind.

Examples

Changing ?x=1&x=2 to ?x=2&x=1 reports x as changed because duplicate value order is significant.

Limitations

  • 65,536 UTF-16 units per URL, 10,000 query pairs per input, 512 KiB combined input, 5 MiB report and 30 seconds.
  • Malformed percent escapes, invalid UTF-8 and empty repeated or trailing query segments are rejected by the strict decoder. Null means key absent; an empty string is a present value.
  • Paths, fragments and cross-key interleaving are not compared. No semantic parameter interpretation, order-insensitive multiset mode or URL fetch.

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