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Row-specific issues
See which record has an unexpected field count or malformed quote.
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CSV Validator
Validate UTF-8 CSV structure, delimiter choice, quoting, header names and consistent column counts before import or conversion.
Validate UTF-8 CSV text Detect comma, semicolon, tab or pipe Find unclosed and unexpected quotes Check consistent column counts
Private browser processing. Your input is processed on this device and is not sent to the Trexmi server.
INPUT CSV to validate *
Paste the source value for this specific transformation. Example: name,version
Trexmi,2
Reading file…
CSV validation result
About the tool
What CSV Validator does
CSV Validator checks the structural problems that commonly break imports: inconsistent field counts, malformed quotes, empty headers, duplicate headers and the wrong delimiter. The result reports whether the document is structurally valid, its row and column counts, the selected delimiter and a list of row-specific issues.
The validator reads quoted fields, including embedded line breaks, and removes a leading UTF-8 byte-order mark before checking the file. It validates table structure rather than business rules: it does not decide whether an email, date, price or product code is correct.
How to use
- Add the complete file. Paste UTF-8 CSV or upload a supported text file.
- Set the delimiter. Choose auto-detect or explicitly select comma, semicolon, tab or pipe.
- Confirm headers. Enable the header option when the first row contains field names.
- Run validation. Review the valid flag, row count, column count and every issue.
- Test the destination. After structural errors are fixed, import a small sample because destination-specific rules are outside this validator.
Built for the task
Why use CSV Validator?
Focused controls, predictable output, and a workflow designed around this exact transformation.
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Column consistency
Compare every logical row with the width established by the first row.
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Header checks
Detect blank and duplicate header names before field mapping fails.
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Structured report
Receive a readable JSON result with validity, dimensions, delimiter and issues.
Useful answers
Questions about CSV Validator
Practical details about input, output, privacy, limits, and the best way to use this tool.
01 What does CSV Validator check?
It checks UTF-8 text, delimiter parsing, quote balance, field counts, empty headers and duplicate headers.
02 Which delimiters are supported?
Comma, semicolon, tab and pipe are supported in automatic or explicit mode.
03 Can quoted fields contain newlines?
Yes. A quoted multiline field is treated as part of one logical record.
04 Does it validate data types?
No. It does not enforce email, date, numeric or business-specific column rules.
05 Why is the first row important?
Its parsed width becomes the expected column count. When headers are enabled, it is also checked for empty and duplicate names.
06 Does it repair the file?
No. It reports structural issues so you can correct the source deliberately.
07 What happens to a UTF-8 BOM?
A leading UTF-8 byte-order mark is removed before delimiter and header checks.
08 Can a valid result still fail to import?
Yes. An importer may require specific columns, types, encodings or regional formats beyond structural CSV validity.
Examples
Find a short row
Every row is compared with the column count of the first record.
Input
sku,price,stock\nTH-01,19.95,4\nTH-02,24.50
Output
Row 3: Expected 3 columns, found 2.
Find a duplicate header
Header comparison is case-insensitive, so ID and id conflict.
Input
ID,Name,id\n1,Ada,42
Output
Row 1: Header contains duplicate column names.
Column-count validation
The first parsed row establishes the expected number of columns. Every later logical record is compared against that width. A mismatch often indicates a missing delimiter, an extra delimiter or malformed quoting earlier in the row.
Quote problems
A double quote may open a quoted field only at a field boundary. Double quotes inside a quoted field must be escaped correctly, and the field must close before the end of the document. The validator reports an unexpected quote or the row where an unclosed quoted field began.
Header validation
When the header option is enabled, every header must be non-empty and unique without regard to letter case. These checks prevent ambiguous mappings such as two email columns. The validator does not enforce a particular spelling or required business field list.
Automatic delimiter detection
Automatic mode tests common separators against the first line. Explicit selection is more reliable for one-column files and exports containing unusual punctuation. A delimiter decision affects every later row, so confirm it in the result before fixing apparent width errors.
Inspect and convert the file
Use CSV Viewer to inspect rows visually, CSV Formatter to normalize a valid file, or CSV to JSON after structure has been checked. None of these replaces destination-specific import validation.
CSV conventions
RFC 4180 describes a common comma-separated format. Applications may use different delimiters and escape rules, so the target platform remains the final authority. Remove confidential records before submitting a production export.