How do I convert a CSV file to JSON in my browser?

Drop a .csv, .tsv or .txt file or paste the text, and the JSON appears next to it. Leave "First row is a header" on for an array of objects, then use Copy, "⬇ JSON" or "⬇ JSONL".

Can it handle commas and line breaks inside quoted CSV fields?

Yes. It uses an RFC 4180 parser, so commas, line breaks and escaped double quotes inside quoted fields stay in one cell instead of splitting the row.

How do I stop ZIP codes and IDs losing their leading zeros?

With "Convert numbers & booleans" on, only lossless numbers are converted. Values like 02138 and integers too large for JavaScript stay as text, so ZIP codes and long IDs are not corrupted.

My CSV uses semicolons and European numbers like 1.234,56. What should I do?

The delimiter is auto-detected, or you can pick Semicolon, Tab, Pipe or Custom. Under Numbers, choose Auto or "Comma decimal, dot thousands" so 1.234,56 becomes a real number.

Can I get JSON keyed by an ID column instead of an array?

Yes. Under Structure choose "Object keyed by a column" and pick the Key column. If two rows share a key, later rows replace earlier ones and a duplicate-key warning appears.

Yes. Every tool is free to use, with no account and no credit card. The work runs on your device rather than on our servers, which is what keeps it free to run.

Are my files uploaded?

No. Your files are opened and processed inside your browser and are not sent to LibraTool. Some tools first download a processing engine or AI model to your browser; that download contains no data of yours.

Does it work on mobile?

Yes. It runs in current mobile browsers on iOS and Android, with nothing to install. Very large files can be slow or run out of memory on a phone, so use a computer for those.

🔄

Free CSV to JSON

Convert CSV (or TSV) into JSON — array of objects or arrays — with a proper RFC 4180 parser, delimiter auto-detection, and type conversion. Runs in your browser.

File size depends on your deviceFiles stay privateNo login requiredFree forever

Works offline once loaded

Drop a CSV file (or paste below)

CSV, TSV, TXT · processed on your device

or press Ctrl+V to paste from your clipboard

Browse files

CSV

JSON

—

First row is a headerConvert numbers & booleansSkip empty linesTrim whitespace in cells

Delimiter

Output

Structure

💡 A proper RFC 4180 parser — handles quoted fields, commas and line breaks inside quotes, and escaped quotes. With 'first row is a header' on, you get an array of objects; off, an array of arrays. Everything runs in your browser. Type conversion is off by default so IDs like ZIP codes (02138), leading-zero codes, and very long numbers keep their exact text — enable 'Convert numbers & booleans' only when you want typed values.

Common uses

Convert CSV to JSON for an APITurn a spreadsheet export into JSON your code or API can consume.
Convert Messy CSV with Quotes and CommasParse CSV that has commas, quotes, or line breaks inside fields.
Convert TSV (Tab-Separated) to JSONParse tab-separated data copied from a spreadsheet.
Prepare CSV Data for ImportConvert a CSV into JSON to seed a database or load into an app.
Quickly Inspect CSV as JSONSee CSV rows as structured JSON objects while developing.

How It Works

CSV looks simple but is full of edge cases — quoted fields, commas inside quotes, line breaks inside cells. This uses a proper RFC 4180 parser so those all work, entirely in your browser.

1
You paste CSV or drop a file
The delimiter (comma, semicolon, tab, or pipe) is auto-detected, or you can set it manually. Nothing is uploaded.
2
It's parsed correctly
Quoted fields, escaped quotes (""), and delimiters/newlines inside quotes are all handled per the CSV spec.
3
You choose the shape
With a header row, each line becomes an object keyed by the headers; without, an array of arrays. Optionally convert numbers and booleans to real types.
4
Copy or download JSON
Get clean, indented JSON ready for your code.

CSVs frequently hold contacts, transactions, and other personal data. Parsing happens entirely on your device — none of it is uploaded.

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