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Compare two CSV files

Match a before/after pair on a key column and see what was added, removed or changed — down to the individual cell.

No uploadNo sign-upCell-level diff
Process your CSV Runs on your device
Drop a CSV here
Select multiple files (two or more)
first file = before, second = after

How to use

  1. Pick the “before” CSV first, then the “after” file.
  2. Choose the key column to match rows on (customer ID, email, …).
  3. Review added / removed / changed, then export the diff as CSV.

What this tool does not do

When a key appears more than once, only the first row is compared. Row order alone is not reported as a difference.

FAQ

Is the key column required?
Yes — rows need a key to be matched. If there is no ID, use email, or name plus company.
What if the column sets differ?
The comparison uses the union of column names, so a column present in only one file still shows up as a difference.
What about a different row order?
It is not treated as a difference — rows are matched on the key.
How do I save the result?
“Download the diff as CSV” exports five columns: type (added / removed / changed), key, column, before, after.

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