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Free JSON to CSV & CSV to JSON Converter

Convert between JSON and CSV in seconds. Supports nested object flattening, custom delimiters (comma, semicolon, tab, pipe), auto-detection, and type coercion. Everything runs in your browser — no upload, no server.

Options

Press Cmd/Ctrl + Enter to convert

How to Convert JSON to CSV

  1. Select the JSON → CSV tab.
  2. Paste a JSON array (or a single JSON object) into the input, or click Load Example.
  3. Choose a delimiter — comma is the universal default.
  4. Click Convert to CSV or press Cmd / Ctrl + Enter.
  5. Copy the output or click Download to save as a .csv file.

How to Convert CSV to JSON

  1. Select the CSV → JSON tab.
  2. Paste your CSV data into the input field.
  3. The delimiter is auto-detected from the first line. Disable this to choose manually.
  4. Toggle Parse numeric strings as numbers and Parse “true”/“false” as booleans to get correctly typed JSON values.
  5. Click Convert to JSON — the output is a formatted JSON array. Download as .json or copy with one click.

Nested Object Flattening

When converting JSON to CSV, nested objects are automatically flattened using dot notation. For example:

// Input JSON
{ "user": { "name": "Alice", "age": 30 }, "active": true }

// Output CSV headers
user.name,user.age,active

// Output CSV row
Alice,30,true

Arrays inside objects are converted to their string representation (e.g., [1,2,3]).

CSV Delimiter Reference

DelimiterCharacterCommon Use Case
Comma,Default CSV — Excel, Google Sheets, most tools
Semicolon;CSV exports from European locales (where , is decimal)
Tab\tTSV (Tab-Separated Values) — useful when values contain commas
Pipe|Legacy data exports, custom pipelines

Frequently Asked Questions

What JSON structure is supported?

The JSON input must be either:

  • An array of objects: [{"a": 1}, {"a": 2}]
  • A single object: {"a": 1, "b": 2} (treated as a one-row CSV)

Arrays of primitives (e.g., [1, 2, 3]) are not supported.

What happens if rows have different keys?

The tool performs a union of all keys across all objects. If a row is missing a key, the corresponding CSV cell will be empty.

Is quoted CSV supported in CSV → JSON?

Yes. RFC 4180-style quoting is fully supported: cells can be wrapped in double quotes, and double-quote characters inside a quoted cell must be escaped by doubling them ("").

Is my data private?

Yes. All conversion logic runs entirely in your browser using JavaScript. No data is ever sent to a server.