LOCAL DATA TOOLS
CSV Compare
Find added, removed and changed records across two exports. Match by stable keys, even when rows move.
Your files stay in this browser. Values stay text: 001 stays 001.
1. Add your CSV files
Original
Updated
Header row required. Up to 2,000,000 characters, 100,000 records, 200 columns and 500,000 cells per input. Files up to 8 MB. Imported line endings are preserved until you edit the text; browser text editing uses LF line endings.
Add both inputs, then read their columns.
2. Map columns and choose keys
Only mapped columns participate in record comparison. Unmapped columns are reported separately.
Row-position matching pairs the first record with the first record. Reordering can appear as changes.
Keys must be populated and unique on both sides. Select multiple columns for a composite key. Changing a key value appears as removed + added.
3. Review differences
| Status / key | Record numbers | Values and changes |
|---|
Raw CSV keeps exact values. Spreadsheet software may interpret formula-like values as formulas. Use JSON to preserve values without opening them as spreadsheet cells.
Exports contain every matching record, not just this preview. JSON retains complete source strings. CSV lists changed cells and added/removed values; unmapped schema columns are also included. Large reports may require a status filter.