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CSV Validator & Repair

Validate malformed CSV files, review safe repairs, and prepare a new copy for import

Validate CSV structure and prepare a repaired copy in one workflow. The checker reports malformed rows, parser errors, header problems, duplicate or empty rows, whitespace, invisible characters, and values that may execute as spreadsheet formulas.

Safe structural repairs are automatic and never discard non-empty cells. Changes that alter content remain explicit options, and formula escaping is off by default because formulas may be intentional.

Everything runs locally in your browser. Review findings, actions, and the before-and-after preview, then download a new CSV and JSON audit report for your import handoff.

Files stay on this deviceRuns entirely in your browserFree — no signup
Versioned public test corpusLocal, cancellable worker

Try a known malformed sample first

Each synthetic CC0 fixture has published hashes, expected findings, allowed repairs, and non-loss invariants. Samples run through this exact validator workflow.

Review corpus evidence

Check structure and prepare safe repairs

Your file is analysed in this browser. It is never uploaded or stored.

Hard input limits: 5 MiB on desktop; 2 MiB on phones and tablets. Larger files are rejected before validation.

Select a delimited text file to analyse immediately.

How to Convert

  1. Upload a CSV, TSV, or TXT file, or paste delimited data
  2. Review detected formatting, validation issues, and repair findings
  3. Choose any optional content changes; structural repairs are applied automatically
  4. Compare the original and repaired table previews
  5. Download the repaired CSV, JSON audit report, or inferred schema

Features

  • Detect delimiters, line endings, parser errors, and inconsistent row widths
  • Find empty or duplicate headers, empty rows, duplicate rows, and risky cell content
  • Preserve non-empty values while extending headers and padding short rows
  • Warn about formula-like cells without changing them by default
  • Optionally trim whitespace, remove empty rows or invisible characters, and escape formulas
  • Compare before-and-after table previews before downloading
  • Download the repaired CSV and a structured JSON audit report
  • Profile original columns and download an inferred JSON Schema

Use Cases

  • Check files before database, CRM, accounting, or ecommerce imports
  • Repair inconsistent vendor and partner exports without losing extra values
  • Diagnose malformed CSV and parser errors before an ETL handoff
  • Standardize headers, row widths, quoting, and line endings
  • Document validation findings and selected repairs for an auditable data workflow

Frequently Asked Questions

What does the CSV repair tool fix automatically?

It removes a leading UTF-8 BOM, names empty headers, makes duplicate header names unique, extends the header when rows have extra cells, pads short rows, and writes consistently quoted CSV output with normalized line endings.

Can repairing a CSV delete my data?

Automatic structural repairs never discard non-empty cells. Extra values extend the output header, and short rows receive empty padding. Removing fully empty rows and other content changes only happens when you select those options.

Why is formula escaping turned off by default?

Values beginning with =, +, -, or @ may execute as formulas in spreadsheet software, but they may also be intentional. The validator always warns about them and only prefixes an apostrophe when you opt in.

Can every malformed CSV be repaired automatically?

No. Parser errors remain visible because missing quotes or ambiguous record boundaries can require a manual decision. The tool preserves the parser output for review and explains the proposed repairs instead of claiming uncertain content is fixed.

What is included in the JSON audit report?

The report records the detected delimiter and line ending, validation counts, findings, selected options, repair actions, before-and-after row and column counts, and the report timestamp.

Is my CSV uploaded to a server?

No. Validation, repair, previews, and downloads all run locally in your browser. Your CSV is not uploaded or stored.

How is this different from CSV Cleaner and CSV Analyzer?

CSV Validator & Repair focuses on structural errors, safe repair, and import readiness. CSV Cleaner is for selected content cleanup, while CSV Analyzer provides deeper descriptive statistics about columns and values.

Can it infer a schema?

Yes. The validator profiles each original column, detects common data types, and can download an inferred JSON Schema. Review repaired header changes separately in the after preview.

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