CSV validator and column profiler

Find the broken rows and see what every column holds.

Use in Claude

Free for 10 runs a day.

A CSV validator report for deals.csv: an unclosed quote on line 6, a duplicate of line 2 on line 4, a blank row on line 5 and a short row on line 6.

Find the line that breaks the CSV

One unclosed quote swallows every row after it. The import fails or shifts columns. The error names no line.

The validator lists every problem in the CSV with its line number.

Know each column before you import

A column called Email holds phone numbers. Half the Amount cells are empty. Nobody notices until a report is wrong.

Every CSV column gets its type, fill rate, distinct count and range.

Use it from a script or an AI agent

Use in Claude

MCP  https://dedupe.ly/tools/mcp   every free tool in one connector (this one: validate_csv)

POST https://dedupe.ly/tools/api/csv-validator
{ "csv": "Email,Amount\nann@x.example,1200\nbad-email,abc" }

Docs https://dedupe.ly/tools/api/openapi.json

OpenAPI document · API index · llms.txt

Questions about validating a CSV

What does the CSV validator check?

Quotes that are never closed or sit in the wrong place, rows with too many or too few fields, blank and duplicate rows, empty or repeated headers, mixed line endings and broken characters.

What is in the column profile?

For each column: its type, how many cells are filled, how many values are distinct or repeated, how many do not fit the type, and its minimum, maximum and most common values.

Which types does it detect?

Email, URL, phone, date, whole number, decimal number, true or false, and text.

Why does a column show invalid values?

Most of the column fits one type and these cells do not, such as bad-email in a column of email addresses or 2026-02-30 in a column of dates.

What do the broken characters mean?

The file was saved in one encoding and read in another, so José shows as JosÃ©. Save it again as UTF-8.

Is my file uploaded?

No. The CSV is checked in your browser and never leaves your computer.

Is it free?

Yes. Ten checks a day, free.