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Runs locally · No uploads · No sign-up

CSVToJSON Free Online CSV to JSON Converter

100% Free, Secure & Browser-Based CSV to JSON Converter & Data Formatter.

CSVToJSON is a free online tool that converts CSV files and pasted CSV text into formatted JSON. It supports comma, tab, semicolon and pipe delimiters, header rows, 2-space, 4-space or minified output, automatic number, boolean and null parsing, and RFC 4180 quoted fields. All parsing happens locally in your browser — files are never uploaded.

JSON indent
More options

CSV Input

Drag & drop a CSV file here

…or click inside and paste raw CSV text

.csv · .tsv · .txt — processed locally, never uploaded

Ready

JSON Output 

// JSON output will appear here as you type…
—

How to convert CSV to JSON online

CSVToJSON turns spreadsheet-style comma-separated values into clean, standards-compliant JSON in three steps — with no software to install and no file uploads.

  1. 01

    Add your CSV

    Drag & drop a .csv or .tsv file, open it from your device, or paste raw CSV text straight into the input pane.

  2. 02

    Tune the options

    Pick a delimiter, toggle the header row, choose 2-space, 4-space or minified output and enable automatic type parsing.

  3. 03

    Copy or download

    Review the highlighted live preview, fix any flagged rows, then copy the JSON or download it as a .json file.

What is CSV to JSON conversion?

CSV (Comma-Separated Values) is a flat, tabular text format exported by Excel, Google Sheets, databases and analytics tools. JSON (JavaScript Object Notation) is the structured data format used by web APIs, JavaScript apps, NoSQL databases and configuration files. Converting CSV to JSON maps each row to a JSON object whose keys come from the header row, so tabular data can be consumed directly by code.

Example

id,name,active
1,"Smith, Jane",true
2,Leo,false
[
  { "id": 1,
    "name": "Smith, Jane",
    "active": true },
  …
]

Why use CSVToJSON?

  • ✓Robust RFC 4180 parser — quoted cells, commas and line breaks inside cells, and escaped "" quotes.
  • ✓Live validation — warns about unclosed quotes, rows with too many or too few fields, and blank or duplicate headers.
  • ✓Smart type parsing — numbers, booleans and null become native JSON types, while ZIP codes and IDs with leading zeros stay strings.
  • ✓Nested output — headers like address.city can become nested JSON objects.
  • ✓Private by design — everything happens in your browser; your data never leaves your device.

Frequently asked questions

How do I convert a CSV file to JSON format online?

▾

Drag and drop your .csv file onto the upload zone (or paste raw CSV into the input box). CSVToJSON parses it instantly and shows the JSON in the live preview pane. Choose your delimiter, header and indentation options, then click Copy JSON or Download .json File.

Are my uploaded CSV data files private and secure?

▾

Yes. CSVToJSON runs 100% in your web browser using JavaScript. Your CSV file is read locally with the FileReader API and is never uploaded to any server, logged or stored. It even keeps working offline once the page has loaded.

How does the converter handle commas inside text cells?

▾

The parser follows RFC 4180. Any cell wrapped in double quotes can contain commas, delimiters and even line breaks, and a doubled quote ("") inside a quoted cell becomes a literal quote character. For example "Smith, John" stays a single value.

Can it convert numbers and booleans to real JSON types?

▾

Yes. With Auto-parse types enabled, unquoted values like 42, -3.14 and 1e5 become JSON numbers, true/false become booleans and null becomes null. Values with leading zeros such as ZIP codes stay strings, and quoted values are always kept as strings.

What if my CSV has no header row?

▾

Turn off First row is headers. Each row is then output as objects with generated keys (column_1, column_2, …) or as plain arrays, depending on the Output structure setting.

Does it support TSV, semicolon or pipe-delimited files?

▾

Yes. Choose Comma, Tab, Semicolon or Pipe from the delimiter menu, or leave it on Auto-detect and CSVToJSON will pick the most likely delimiter from the first lines of your data.

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