What does the header row option do?

With it on, the first row supplies the keys and every later row becomes an object. With it off, each row becomes an array of values — handy for raw matrices or files without column names.

How does delimiter auto-detection work?

The converter looks at the first line and counts commas, semicolons, tabs, and pipes, then picks whichever appears most often. If it guesses wrong, switch the dropdown to force the exact delimiter.

Are numbers and booleans converted to real types?

Yes, when 'Typed values' is on. A cell like 42 becomes the number 42 and true becomes a boolean. Codes with leading zeros such as 007 stay as strings so nothing is mangled. Turn the toggle off to keep every value as text.

Does it handle commas and quotes inside a field?

Yes. The parser follows RFC 4180, so a quoted field can contain commas, line breaks, and escaped double quotes ("") without breaking the row.

Is my data uploaded anywhere?

No. Parsing runs entirely in your browser with JavaScript. Your CSV never leaves the page — nothing is sent to a server, logged, or stored.

CSV to JSON Converter — Free, Instant, In Your Browser

CSV input

JSON output

Delimiter

Header row Typed values

0 rows · 0 columns

Paste CSV or drop in a .csv file and get a tidy JSON array back. The converter auto-detects whether your data is comma, semicolon, or tab separated, turns the header row into object keys, and quietly converts numbers and true/false to real JSON types. Everything runs in your browser — nothing is uploaded.

How it works

1
Paste or upload CSV Drop CSV text into the input panel, or click Upload to load a .csv file from your computer.
2
Set the options Leave the delimiter on Auto or force comma, semicolon, or tab. Toggle the header row and type detection to match your data.
3
Copy or download The JSON updates as you type. Click Copy to grab it, or Download to save a .json file.

Your data stays private

All processing happens entirely in your browser. No files, text, or data are ever sent to our servers. You can disconnect from the internet and this tool will still work.

Frequently asked questions

What does the header row option do?: With it on, the first row supplies the keys and every later row becomes an object. With it off, each row becomes an array of values — handy for raw matrices or files without column names.
How does delimiter auto-detection work?: The converter looks at the first line and counts commas, semicolons, tabs, and pipes, then picks whichever appears most often. If it guesses wrong, switch the dropdown to force the exact delimiter.
Are numbers and booleans converted to real types?: Yes, when 'Typed values' is on. A cell like 42 becomes the number 42 and true becomes a boolean. Codes with leading zeros such as 007 stay as strings so nothing is mangled. Turn the toggle off to keep every value as text.
Does it handle commas and quotes inside a field?: Yes. The parser follows RFC 4180, so a quoted field can contain commas, line breaks, and escaped double quotes ("") without breaking the row.
Is my data uploaded anywhere?: No. Parsing runs entirely in your browser with JavaScript. Your CSV never leaves the page — nothing is sent to a server, logged, or stored.

From the blog

CSV to JSON: Delimiters, Quotes, and the Leading-Zero Trap How header rows become keys, why auto-detection beats guessing the delimiter, and the type-coercion gotcha that eats your ZIP codes. Read the post →

CSV to JSON Converter — Free, Instant, In Your Browser

How it works

Your data stays private

Frequently asked questions

From the blog

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