CSV cleaner, converter & compare
Clean duplicate rows, preserve leading zeros and compare two datasets by a unique key. All processing stays in your browser.
The first row must contain unique column headers.
Compare exports without losing your IDs.
Import a CSV, trim whitespace and remove duplicate rows. With a key column, deduplication keeps the first row for each key. Without a key, it compares whole rows. All CSV values remain strings so leading zeros stay intact.
Old file versus new file
Paste the older file first and the newer file second. Choose an exact unique header such as sku or email. Duplicate or blank comparison keys are rejected instead of silently overwriting records. Added, removed and changed values are reported separately.
Export safely
Spreadsheet-safe CSV export prefixes formula-like cells with an apostrophe to reduce spreadsheet formula execution. This changes those cell values deliberately; disable it only for trusted data. JSON and JSONL exports preserve the cell text. JSON arrays use the union of keys; nested values become JSON strings.
Limits
Parsing and comparison use browser memory, not a server. Very large files can slow the tab. Preview displays 100 rows; exports contain all processed rows. No cloud history is stored.
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