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CSV Diff

Your data never leaves your device

How to Use

  1. 1. Upload both files — Drop the original CSV on the left and the modified CSV on the right.
  2. 2. Compare — Click Compare to run the diff algorithm.
  3. 3. Review changes — Green rows are added, red are removed, amber are modified.
  4. 4. Switch views — Toggle between side-by-side and unified diff views.

Frequently Asked Questions

Is my data safe?
Yes. Both files are compared entirely in your browser. Nothing is uploaded — your data never leaves your device.
How does the comparison work?
CSVArc uses a Longest Common Subsequence (LCS) algorithm to align rows between the two files, then identifies added, removed, and modified rows with cell-level change detection.
Can I compare large files?
Yes. For files where neither exceeds 10,000 rows, the full LCS algorithm is used for maximum accuracy. When either file exceeds 10,000 rows, a faster hash-based comparison provides results in seconds.
What if the files have different columns?
CSVArc handles different column counts by padding the shorter file. Changed columns are highlighted individually.