Is it safe to use the CSV ↔ JSON online?

Yes — and ours is safer than most. Many free online tools quietly upload your files to their servers to do the work. We don't. Everything happens inside your browser on your own device, so your files never reach the internet. There's no upload step, no server copy, and no way for us (or anyone else) to see what you're working on.

Are my files uploaded to a server?

No. There's no server-side processing here. The whole tool is a tiny app that runs in your browser — we don't even have a server that could receive your files. You can confirm this by opening your browser's network tab while you use the tool: nothing leaves your device.

Do I need to sign up or pay?

No. There's no account, no email collection, no credit card. The tool is free to use as much as you want, on as many files as you want. We're supported by a few unobtrusive ads on the page — not by your data.

Are nested JSON objects flattened?

Nested objects/arrays are JSON-stringified into single CSV cells. CSV doesn't have a native nested format.

What if my CSV has no header?

Toggle 'has header'. With it off, JSON output uses positional keys (col1, col2, ...).

CSV ↔ JSON Converter

Convert between CSV and JSON. RFC 4180 quoting handled correctly — commas, quotes, and newlines inside fields all work. Pick your delimiter (comma, tab, semicolon).

Features

CSV → JSON array of objects (uses first row as keys)
JSON → CSV with auto-generated header
RFC 4180 quoted fields, including embedded commas/quotes/newlines
Custom delimiter: comma, tab, semicolon, pipe
Optional trim of whitespace around fields

How to csv ↔ json converter

Pick direction — CSV → JSON or JSON → CSV.
Paste input — Output updates live.
Adjust delimiter — Tab or semicolon if your data uses those.

Frequently asked questions

Is it safe to use the CSV ↔ JSON online?: Yes — and ours is safer than most. Many free online tools quietly upload your files to their servers to do the work. We don't. Everything happens inside your browser on your own device, so your files never reach the internet. There's no upload step, no server copy, and no way for us (or anyone else) to see what you're working on.
Are my files uploaded to a server?: No. There's no server-side processing here. The whole tool is a tiny app that runs in your browser — we don't even have a server that could receive your files. You can confirm this by opening your browser's network tab while you use the tool: nothing leaves your device.
Do I need to sign up or pay?: No. There's no account, no email collection, no credit card. The tool is free to use as much as you want, on as many files as you want. We're supported by a few unobtrusive ads on the page — not by your data.
Are nested JSON objects flattened?: Nested objects/arrays are JSON-stringified into single CSV cells. CSV doesn't have a native nested format.
What if my CSV has no header?: Toggle 'has header'. With it off, JSON output uses positional keys (col1, col2, ...).