csv2json

Convert between CSV and JSON in both directions, with automatic type inference and a proper RFC 4180 parser (quoted fields, escaped quotes, embedded newlines). Zero dependencies.

The companion to csv-peek (which previews CSVs). Unlike csvkit (Python) or paste-it-here websites, this runs locally and never uploads your data.

Install

npm install -g csv2json

Or without installing:

npx csv2json data.csv

Usage

csv2json users.csv                    # CSV → JSON on stdout
csv2json users.csv -o users.json      # CSV → JSON file
csv2json users.json -o users.csv      # JSON → CSV
csv2json data.tsv -d tab              # Tab-separated input
cat export.csv | csv2json - --compact # From stdin, single-line JSON

Direction is inferred from the file extension (or the -o target), and falls back to sniffing the content. Force it with --from csv|json.

Example

users.csv:

id,name,active,score
1,Alice,true,9.5
2,Bob,false,7

csv2json users.csv:

[
  { "id": 1, "name": "Alice", "active": true, "score": 9.5 },
  { "id": 2, "name": "Bob", "active": false, "score": 7 }
]

Note that 1→number, true→boolean, 9.5→float automatically. Disable with --no-type.

Reverse it — csv2json users.json -o users.csv — and you get the CSV back.

Type Inference

| CSV value | JSON value | |---|---| | 42 | 42 (number) | | 3.14 | 3.14 (number) | | true / false | boolean | | null | null | | empty cell | "" (or null with --empty-as-null) | | anything else | string |

Turn it off with --no-type to keep every value a string.

Options

| Flag | Description | |---|---| | --from <csv\|json> | Force input format (for stdin / odd extensions) | | -o, --out <file> | Write to a file (format from its extension) | | -d, --delimiter <d> | , ; \| or tab (default: auto-detect) | | --no-header | CSV has no header → arrays of values | | --no-type | Keep all values as strings | | --empty-as-null | Empty CSV cells become null | | --skip-empty | Omit empty cells from JSON objects | | --pretty / --compact | JSON formatting (pretty is default) |

Nested Values

When converting JSON → CSV, nested objects/arrays in a cell are serialized as JSON strings (and properly quoted). The header row is the union of all keys across every record, in first-seen order.

License

MIT

Keywords

csv to json · json to csv · convert csv · csv json converter · csvkit alternative · rfc 4180 · parse csv · tsv to json · zero dependencies · cli

Built to solve, shared to help — Rushabh Shah 🛠️✨

One of 40+ zero-dependency developer CLI tools — no node_modules, ever.