Why did my ID lose its leading zero?

Type conversion turned it into a number, and 007 as a number is 7. Turn off “Convert numbers and booleans” and every value stays a string exactly as written.

Can it handle fields containing commas or line breaks?

Yes, provided they are quoted as the CSV format requires. The parser handles quoted fields, doubled quotes inside them, and newlines within a quoted value.

My first row is data, not headers.

Turn off “First row is a header” and each record becomes an array of values rather than an object with named fields.

What does the warning about rows that did not parse mean?

Usually that a row has more or fewer fields than the header. The tool converts what it can and tells you which row was first affected, rather than discarding the file.

CSV to JSON

Parse CSV into JSON, quoted fields and all.

Everything runs inside your browser. Your files never leave your device.

Input

Result

The result appears here as you type.

Ask about CSV to JSON

Questions about what this tool does, which option to pick, or what it can and cannot handle.

This is the one part of the site that uses a server. The question you type here is sent to an AI provider to be answered — your files and whatever you put in the tool above are not, and the assistant cannot see them. Answers are generated and can be wrong; the tool itself is not guessing.

About the CSV to JSON

CSV looks trivial until you meet a real one. A field containing a comma, a value wrapped in quotes with a quote inside it, a description with a newline in the middle, a file that uses semicolons because it was exported in Germany — a naive split on commas breaks on all of them. This converter uses a proper CSV parser, so quoted fields, escaped quotes and embedded newlines come through intact.

Delimiter detection is automatic by default, and usually right; you can force comma, semicolon, tab or pipe when the guess is wrong or the file is ambiguous.

The option worth thinking about is type conversion. With it on, “1” becomes the number 1 and “true” becomes a boolean, which is what you want for data you are about to compute with. With it off, everything stays a string — and that is what you want for identifiers. A postcode, an order number or an account code with a leading zero loses that zero the moment it becomes a number, and the damage is permanent and silent. If your CSV contains identifiers, turn typing off.

Rows that do not parse cleanly are reported above the result rather than causing the whole file to fail, so one ragged line does not cost you the other nine hundred.

How to use it

1Paste your CSV, or the contents of a .csv file, into the input box.
2Leave the delimiter on automatic unless the columns come out wrong, then pick it explicitly.
3Turn off “Convert numbers and booleans” if your data contains IDs, postcodes or anything with a leading zero.
4Copy the JSON array, or download it as a .json file.

Questions

Why did my ID lose its leading zero?: Type conversion turned it into a number, and 007 as a number is 7. Turn off “Convert numbers and booleans” and every value stays a string exactly as written.
Can it handle fields containing commas or line breaks?: Yes, provided they are quoted as the CSV format requires. The parser handles quoted fields, doubled quotes inside them, and newlines within a quoted value.
My first row is data, not headers.: Turn off “First row is a header” and each record becomes an array of values rather than an object with named fields.
What does the warning about rows that did not parse mean?: Usually that a row has more or fewer fields than the header. The tool converts what it can and tells you which row was first affected, rather than discarding the file.