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CSV Data Validator

Check field rules and download record-level CSV and JSON validation reports.

Choose your file

Private by designProcessed locally · Originals unchanged

Validation rules

Open to match the rules to your file. Current example uses email.

Choose local input and settings.

Preview & downloads

Your result will appear here

Choose a file, adjust the settings and select Validate File.
How to use, limits & privacy
Edit the rules array using existing column names. Rules: required, number, integer, email, date, oneOf, unique. oneOf needs a values array of strings. date accepts real YYYY-MM-DD dates; integer requires an exact browser-safe integer. Optional rules skip empty strings; required rejects whitespace-only cells. Unique flags later repeated nonempty values. Record numbers include the header and count multiline quoted records once. Email checks are syntax heuristics. CSV error exports protect formula cells.
Text: UTF-8 only, 4 MiB; CSV: 50,000 data records, 200 columns, 500,000 cells; exports: 16 MiB.
Inputs are never uploaded. Results are rendered as text or a locally generated image. Original files remain unchanged. Changing input invalidates previous results.