Free CSV to JSON converter

Paste spreadsheet or API export CSV and get a pretty-printed JSON array of objects. Delimiter auto-detection, optional first-row headers, dot notation unflattening (pairs with JSON to CSV), and light type inference — all in your browser.

For round-trips with JSON to CSV, keep dotted column names and enable unflatten nested keys.

Delimiter

Detected: comma-separated

First row is headerUnflatten dotted keys (usage.local → nested object)Infer numbers and booleans from cells

CSV input

JSON output

2 data rows

[
  {
    "id": 1,
    "name": "Alice",
    "plan": "Pro",
    "usage": {
      "uploads": 0,
      "local": true
    }
  },
  {
    "id": 2,
    "name": "Bob",
    "plan": "Free",
    "usage": {
      "uploads": 0,
      "local": true
    }
  }
]

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How to use this tool

1
Open CSV to JSON converter
Turn spreadsheet exports into JSON for apps and scripts.
2
Paste CSV and set options
Choose delimiter mode, headers, unflatten, and type inference.
3
Copy or download JSON
Copy the JSON array or download data.json.

Quick facts

Runs locally?	Yes — parsing uses Papa Parse in your browser only.
Is anything uploaded?	No. CSV stays in this tab.
Works with JSON to CSV?	Yes — enable unflatten for dotted columns produced by the JSON to CSV tool.
Excel paste?	Tab-separated paste from spreadsheets is detected automatically.

Top use cases

CSV to JSON array in browser, auto delimiter, dot-key unflatten, type inference — no upload.
Runs locally?: Yes — parsing uses Papa Parse in your browser only.
Is anything uploaded?: No. CSV stays in this tab.
Works with JSON to CSV?: Yes — enable unflatten for dotted columns produced by the JSON to CSV tool.
Excel paste?: Tab-separated paste from spreadsheets is detected automatically.

FAQ

Why is output always an array?▾

Each CSV row becomes one JSON object in an array — standard for APIs and scripts.

What if my CSV has no header row?▾

Turn off “First row is header” to use column1, column2, … as keys.

Does it parse JSON inside cells?▾

With type inference on, cell values that look like JSON arrays or objects are parsed.

UTF-8 BOM from Excel?▾

Leading BOM in the file text is handled by the parser library.

Huge files?▾

Very large CSV may slow the tab — split files if the browser struggles.

Custom delimiters like semicolon?▾

This version supports comma and tab. Convert semicolon CSV in a sheet first or use comma export.