How do I validate a CSV file online?

Drag, choose, or paste your CSV, XLSX, or JSON data into Data Quality, select a worksheet if an Excel file requires it, and click Validate. The results identify columns that need review.

Is there a free CSV validator with no file upload?

Yes. Paste tabular data into the Data Quality drop area, then click Validate just as you would after choosing a file.

How do I run Excel data quality checks in the browser?

Open Data Quality, choose or paste an XLSX file, select the worksheet to check, and click Validate. Missing values, duplicates, bad dates, and type errors are flagged without leaving your browser.

Free CSV Validator & Excel Data Quality Checker

Data Quality

What gets checked

Missing & blank values
Duplicate rows & IDs
Type & format mismatches
Outliers & rare categories
Inconsistent dates & numbers

Everything runs in your browser — your file never leaves your device.

Drop a CSV, Excel, or JSON file. Missing values, type mismatches, and column issues surface in seconds—your data never leaves the browser.

Drag & drop, or click to choose CSV, XLSX, JSON, or NDJSON

Choose a file above to validate it.

Data Quality

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Data quality FAQ

How do I validate a CSV file online?

Is there a free CSV validator with no file upload?

How do I run Excel data quality checks in the browser?