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CSV Diff — Compare Two CSVs by Key

Compare 2 CSVs by key column. Detects added/removed/changed rows (which cell changed, from what to what). Supports , ; tab | delimiters.

CSV A (original)

CSV B (new)

Key column

Index 0 = first column. Used to match rows between A and B.

Delimiter

First row is header

Compare 2 CSVs by key column. Detects added/removed/changed rows (which cell changed, from what to what). Supports delimiters , ; tab |.

When to use CSV Diff

Track product catalogs: dump this week's price list vs last week's — see which prices changed.
Database migrations: export old + new tables → check missing rows and schema changes.
Audit data imports: before/after importing a CSV into the DB — verify row counts.
HR / payroll: this month's roster vs last month's — who joined, who left, who got a raise.
Finance reconciliation: compare transaction logs from 2 sources (bank + accounting).

The tool matches rows between A and B by a key column (first column by default). Then:

For changed rows, the tool highlights which cells changed (red strikethrough for the old value, green for the new).

Pick the right key column: ID, SKU, email — anything unique. Avoid names (can collide).
Composite keys: the tool only supports a single column. For composite keys, pre-build a combined column (e.g. user_id-date).
Excel data: export to CSV with "," delimiter (US/VN) or ";" (EU).
Privacy: runs 100% in your browser. Sensitive data stays local.