Are my CSV files uploaded anywhere?

No. This conversion runs entirely inside your browser, so the file never leaves your device. You can confirm it yourself: open the network tab of your browser's developer tools and watch that nothing is sent while the file converts.

What shape is the JSON output?

An array of objects, with the header row supplying the keys — the shape almost every API, seed script and test fixture expects.

Are numbers converted to real JSON numbers?

Yes. Values that look numeric become JSON numbers rather than strings, and true and false become booleans. That is usually what you want for quantities and flags, and the wrong answer for identifiers.

What happens to leading zeros?

They are lost, because `007` read as a number is `7`. Product codes, postcodes and account references are the usual casualties. If your data has them, check the output before relying on it.

Does it handle quoted fields and commas inside a cell?

Yes. Quoted fields, escaped quotes and newlines inside a cell are all parsed properly rather than split naively on commas, so an address column survives the conversion intact.

Is there a row limit?

None imposed by us. The parser runs on your own machine, so the practical ceiling is your available memory rather than a plan tier or a queue.

CSVtoJSON

Convert CSV to JSON

Up to 3 files at once, 100 with Pro. Mixed formats are fine.

Converting CSV to JSON here gives you an array of objects, using the header row as the keys — the shape most APIs and test fixtures expect. Quoted fields and embedded commas are parsed correctly, numeric values become real numbers, and the whole thing runs in your browser, so a customer export never leaves your machine.

Why convert CSV to JSON at all

CSV is what every database, spreadsheet and analytics tool exports, and JSON is what every API, test fixture and configuration file expects. The gap between them is small and tedious, which is exactly the kind of gap worth having a tool for rather than writing a throwaway script each time.

The output: an array of objects keyed by the header row

The header row supplies the keys and every following row becomes one object — the shape almost everything downstream assumes. Quoted fields, escaped quotes and newlines inside a cell are parsed properly, so a CSV containing commas in an address field survives it, which a naive split on commas does not.

Type inference, and where it will bite you

Types are inferred, and that is the part worth checking. Numeric-looking values become JSON numbers and `true`/`false` become booleans, which is nearly always what you want for quantities and flags.

It is the wrong answer for identifiers. `007` becomes `7`, and a postcode, a part number or a zero-padded account reference loses its leading zeros silently. If your data contains codes rather than quantities, look at the output before you rely on it — this is the single most common way a CSV to JSON conversion produces valid JSON and wrong data.

Converting a customer export without uploading it

The whole thing runs in your browser, so a large export converts as fast as your machine allows and never leaves it. That matters more for this pair than for most: a CSV is very often a customer list, an order history or an export from a system somebody would rather not describe to a third party.

How to convert CSV to JSON

Drop your CSV onto this page, or click to choose one.
It parses and converts in your browser.
Download the JSON.

CSV vs JSON: rows of text against structured data

CSV compared with JSON
	CSV	JSON
Full name	Comma-Separated Values	JavaScript Object Notation
File extension	.csv	.json
Media type	text/csv	application/json

Quality: Nothing is lost. The result holds exactly the same picture, text or data as the original.
Where it runs: This conversion runs inside your browser. Your file is never uploaded, and it works with the network disconnected.

CSV to JSON: the questions that matter for real data

Are my CSV files uploaded anywhere?: No. This conversion runs entirely inside your browser, so the file never leaves your device. You can confirm it yourself: open the network tab of your browser's developer tools and watch that nothing is sent while the file converts.
What shape is the JSON output?: An array of objects, with the header row supplying the keys — the shape almost every API, seed script and test fixture expects.
Are numbers converted to real JSON numbers?: Yes. Values that look numeric become JSON numbers rather than strings, and true and false become booleans. That is usually what you want for quantities and flags, and the wrong answer for identifiers.
What happens to leading zeros?: They are lost, because `007` read as a number is `7`. Product codes, postcodes and account references are the usual casualties. If your data has them, check the output before relying on it.
Does it handle quoted fields and commas inside a cell?: Yes. Quoted fields, escaped quotes and newlines inside a cell are all parsed properly rather than split naively on commas, so an address column survives the conversion intact.
Is there a row limit?: None imposed by us. The parser runs on your own machine, so the practical ceiling is your available memory rather than a plan tier or a queue.