CSV Validator & Viewer
Validate CSV structure, preview data in a table format, and convert to JSON. Supports custom delimiters and quoted values.
Formatting
Use quotes to wrap values containing commas or newlines. Double quotes escape quotes.
Delimiters
Common delimiters: comma (,), semicolon (;), tab, and pipe (|).
Headers
First row can be column headers. All rows must have the same number of columns.
About the CSV Validator
This CSV validator detects the delimiter, checks that every row has the same number of columns, and previews the parsed table — which is how you find the rows that will break an import before you run it.
A CSV validator exists because CSV has no real specification and every producer bends it differently. Delimiters vary, quoting is inconsistent, and a file that opens fine in one tool fails in the next.
Mismatched column counts are the error that actually breaks imports. One row with an extra field — usually an unescaped comma inside a value — and a strict importer rejects the whole file. Finding that row in a 50,000-line export by eye is not practical.
The delimiter guess matters too. Semicolon-separated files are the European norm because the comma is the decimal separator there, and a parser assuming commas reads each line as a single column. The parsed preview makes both problems obvious immediately.
How to use the CSV Validator
- Paste the CSV. Paste the raw text, or load the sample to see how it works.
- Confirm the delimiter. Check the detected separator is the right one.
- Review the row check. See any rows whose column count does not match the header.
- Read the preview. Confirm the parsed table looks like the data you expect.
CSV Validator features
- Automatic delimiter detection
- Column count check against the header row
- Parsed table preview
- Handles quoted fields containing commas and newlines
- Reports the specific rows that fail
- Runs entirely in your browser
Frequently asked questions
Why does my CSV import fail?
Usually one row has a different column count from the header, generally an unescaped comma inside a value.
How is the delimiter detected?
By analysing the first rows. Comma, semicolon and tab separated files are all recognised.
Why would a CSV use semicolons?
It is the European convention, because the comma is the decimal separator there. A comma-assuming parser reads each line as one column.
Are quoted fields handled?
Yes. Quoted fields containing commas or line breaks are parsed correctly rather than splitting the row.
Is my file uploaded?
No. Parsing and validation happen entirely in your browser.