Does the first row have to be a header?

It is treated as one by default, and its values become the object keys. A file without a header produces objects keyed by column position instead.

Are numbers converted to numbers?

Only if you ask. Leaving them as text is the safe default: automatic conversion silently ruins postcodes, phone numbers, product codes and any identifier with a leading zero.

What about semicolon-separated files?

Common in locales where the comma is the decimal separator. Set the delimiter and the rest works the same way.

Why does my file have a strange character at the start?

A byte order mark, added by Excel when saving as CSV UTF-8. It is stripped here, but it is worth knowing about — left in place it becomes part of your first column's name and breaks lookups in ways that are hard to see.

CSV to JSON Converter

Parses CSV into JSON, handling the quoted fields, embedded newlines and inconsistent row lengths that real exported files contain.

Runs in your browser — nothing is uploaded

CSV

JSON

Your result appears here. Everything runs in your browser.

Need this as an API?

Why use it

Built to be genuinely useful

Understands quoted fields

Commas and newlines inside a quoted value do not split the row. Splitting on commas is the obvious approach and it is wrong for most real files.

Handles a ragged file

Rows with fewer columns than the header are filled rather than discarded, and rows with more are reported rather than silently truncated.

Nothing is uploaded

It runs in your browser. Tokens, keys and customer data routinely end up in these tools, and none of it should have to cross a network to be decoded.

Free, no sign-up

No account, no daily cap, and no feature held back behind a paywall.

How it works

Three steps

1
Paste the CSV, or open the file.
2
Convert.
3
Copy the JSON, or download it.

Why splitting on commas does not work

The first row that contains an address defeats it. Quoted fields exist precisely so a value can contain the delimiter, and any parser that ignores quoting will split such a row into the wrong number of pieces — shifting every field after it.

The same applies to newlines. A quoted field may contain one, which means a CSV row is not the same thing as a line of the file. A parser that reads line by line will treat one record as two, and the second will be missing its leading columns.

Types, and the decision this tool makes

CSV has no types. Everything in the file is text, and converting to JSON forces a decision about whether 007 is a number, whether true is a boolean, and whether an empty cell is an empty string or null.

Guessing wrong destroys data — a postcode that becomes a number loses its leading zero, and an identifier that becomes a float loses precision. Values are therefore kept as strings unless you ask otherwise, which is the choice that cannot lose information.

FAQ

Questions people ask

API access

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