CSV ⇄ JSON Converter
Convert between CSV and JSON in either direction — auto-detected, with type inference, quoted fields, and custom delimiters. Runs entirely in your browser, no upload, no sign-up.
CSV ⇄ JSON converter
Paste CSV or JSON and convert it to the other format — both directions, right in your browser. Nothing is uploaded: the conversion runs locally in WebAssembly, so your data never leaves your device.
How it works
- Direction — leave it on auto and the tool detects the input (text that
starts with
[or{is treated as JSON and converted to CSV; anything else is parsed as CSV and converted to JSON). Force a direction if you need to. - CSV → JSON — with first row is headers on (the default) you get an array
of objects keyed by the header names; turn it off to get an array of arrays.
Numbers,
true/false, and empty cells are inferred as JSON numbers, booleans, andnull. Values that wouldn't round-trip (leading zeros like007,+1) stay strings, so zip codes and phone numbers are preserved. - JSON → CSV — pass an array of objects (the column order is the union of all
keys, in first-seen order) or an array of arrays. Nested objects and arrays are
written as compact JSON in the cell so nothing is dropped — or turn on
flatten to expand them into dot-notation columns instead (
{"addr":{"city": "NYC"}}becomes anaddr.citycolumn). - Delimiter — use any single character, or the words
tab,comma,semicolon, orpipe. Quoted fields and embedded commas/newlines are handled per RFC 4180.
Examples
name,age / Alice,30 → [{"name":"Alice","age":30}]
[{"a":1,"b":2},{"a":3,"c":4}] → a CSV with columns a,b,c and blank cells where
a row is missing a key.
FAQ
Is my data uploaded anywhere?
No. The converter is compiled to WebAssembly and runs entirely in your browser tab.
Does it support TSV?
Yes — set the delimiter to tab.
Why did my number stay a string?
Values with leading zeros or a leading +
are kept as text so they survive the round trip unchanged.
Developer & Automation Access
Run it from the terminal
Same engine as this page, headless — via the gizza CLI:
gizza tool csv-json-convert "name,age
Alice,30
Bob,25"New to the CLI? Get gizza →
Open it by URL
Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:
https://gizza.ai/tools/csv-json-convert/?data=name%2Cage%0AAlice%2C30%0ABob%2C25&direction=auto&delimiter=%2C&headers=true&pretty=true&flatten=trueMachine-readable descriptor: tool.json — title + parameters JSON Schema for agents.