CSV ↔ JSON Converter 🔒 Your data never leaves your browser.
CSV to JSON objects and back — quotes and delimiters handled.
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About this tool
CSV is how spreadsheets speak; JSON is how APIs speak. This converter bridges them: the first CSV row becomes object keys, numeric-looking values become numbers, and quoted fields with commas or newlines are parsed correctly. Going the other way, it derives columns from the union of all object keys.
The delimiter is auto-detected (comma, semicolon, tab, pipe) — European Excel exports with semicolons just work. Everything runs locally; your data stays on your machine.
Frequently asked questions
Is my file uploaded to a server?
No. Parsing and conversion run entirely in your browser, whether you paste text or drop a file — nothing is uploaded.
How does the tool handle commas inside a quoted CSV field?
Quoted fields (wrapped in "...") can contain commas, line breaks, and escaped double quotes ("") without breaking column alignment — the parser tracks quote state character by character rather than just splitting on commas.
What happens if my CSV doesn't have a header row?
Turn off "First row is header" and the tool treats every row as data, naming columns col1, col2, and so on. Leave it on for normal CSV where the first line names the fields.
Why did JSON → CSV fail with "needs an array of objects"?
The converter expects the top-level JSON value to be an array like [{...}, {...}] — one object per row. A single object, or an array of arrays or plain strings, has no way to become table columns, so wrap or reshape your data first.
How is the delimiter (comma, semicolon, tab) detected?
When "Auto" is selected, the tool samples the first rows and picks whichever of comma, semicolon, tab, or pipe produces the most consistent field count. You can always force a specific delimiter from the dropdown if detection guesses wrong.