CSV to JSON

The CSV to JSON Converter is a free, browser-based tool that transforms comma-separated values files into JSON format. Paste any CSV data, configure your delimiter and output format, and get clean, properly typed JSON in seconds. All processing runs entirely in your browser — nothing is uploaded.

Features

How to Use

1. Paste CSV data into the CSV input area, or click Load to open a file.
2. Choose a delimiter, or leave it on Auto-detect.
3. Select an output format and indentation level.
4. Toggle First row is header and Auto-convert numbers & booleans as needed.
5. Click Convert to JSON.
6. Click Copy to copy to the clipboard, or Download to save output.json.

Output Formats

Array of Objects (default)

Each CSV row becomes a JSON object, with keys taken from the header row:

name,age
Alice,30
Bob,25

becomes:

[
  { "name": "Alice", "age": 30 },
  { "name": "Bob",   "age": 25 }
]

This is the most common format, compatible with most REST APIs and JavaScript applications.

Array of Arrays

Each row (including the optional header row) becomes a JSON array of values:

[
  ["name", "age"],
  ["Alice", 30],
  ["Bob", 25]
]

Useful when column names are separate metadata, or when working with matrix-style data.

Keyed by First Column

The first column's value becomes the key of the top-level JSON object. Useful when the first column contains unique identifiers:

{
  "Alice": { "name": "Alice", "age": 30 },
  "Bob":   { "name": "Bob",   "age": 25 }
}

Auto-detect Delimiter

When set to Auto-detect, the tool scans the first 2000 characters of the input, counts how often each candidate delimiter (comma, semicolon, tab, pipe) appears outside quoted fields, and selects the one that appears most frequently. The detected delimiter is shown in the stats bar after conversion.

If your file uses an unusual delimiter, choose it manually from the dropdown.

Type Coercion

When Auto-convert numbers & booleans is enabled:

Disable this option if you want all values output as strings, which avoids ambiguity for fields that look numeric but should stay as strings (e.g. phone numbers, postal codes, ID strings with leading zeros).

Handling Quoted Fields

The parser is RFC 4180 compliant. It correctly handles:

• Quoted fields containing the delimiter: "New York, NY" is parsed as a single field.
• Quoted fields containing newlines: multi-line cell values are preserved.
• Escaped double quotes: "" inside a quoted field is decoded as a single ".

Use Cases

API Development

Many data sources expose CSV exports. Convert them to JSON to feed mock data into REST APIs, test fixtures, or frontend prototypes.

Database Seeding

Convert CSV exports from spreadsheets into JSON arrays for use as seed files in Node.js, Python, or PHP database seeding scripts.

Data Integration

Transform exported reports from analytics tools, CRMs, or ERP systems into JSON for import into other platforms.

Configuration Files

Some tools accept JSON configuration arrays. If your configuration is maintained in a spreadsheet, export it as CSV and convert it here.

Frontend Development

Hardcode lookup tables, option lists, or reference data as JSON arrays in your application by converting from a CSV maintained in a spreadsheet.

Data Validation

Converting CSV to JSON makes it easy to inspect data types and structure — a useful step when troubleshooting import errors or data pipeline issues.