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CSV data quality checker

Run explicit rules like required, unique, type, range, length, allowed values, and pattern over a CSV and get a pass rate with the failing rows.

Paste or drop a CSV and press Check data.

The checker reports, it never edits: rows are scored against your rules and failures are located, but the data itself is left exactly as pasted. File line numbers come from a quote-aware scan, so a quoted field holding a line break still points at the true line. Null cells are skipped by every rule except required, which keeps one missing cell from failing three rules at once. The per-rule score and the headline pass rate answer different questions: a column can score 90% while the file holds far fewer fully clean rows. Everything runs in this tab; nothing is uploaded.
OptionsCheck data

More config file tools

- CSV studio (/config/csv)
- CSV → SQL (/config/csv-to-sql)
- SQL to CSV (/config/sql-to-csv)
All config file tools (/config)

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Canonical HTML: https://nutter.tools/config/csv-data-quality-checker
Markdown version: https://nutter.tools/config/csv-data-quality-checker.md
Plain-text version: https://nutter.tools/config/csv-data-quality-checker.txt
Agent index: https://nutter.tools/llms.txt