How do I convert CSV to JSON?

Paste your CSV data into the input box above and click Convert. The first row is used as JSON keys by default. Each subsequent row becomes a JSON object in the output array.

Does this tool support TSV files?

Yes. Select Tab as the delimiter or use Auto-Detect and the tool will automatically recognize tab-separated values and convert them to JSON.

Yes. All parsing happens 100% in your browser. No data is uploaded to any server. Your CSV stays on your device.

CSV to JSON Converter Online — Free & Client-Side

CSV Input

Delimiter:

First Row as Headers

Indent:

Parse Numbers

JSON Output

How to Convert CSV to JSON Online

CSV (Comma-Separated Values) is the standard output format for databases, spreadsheets, CRMs, and financial exports. However, when building modern web applications, APIs, or feeding data into JavaScript applications, JSON (JavaScript Object Notation) is required. This utility converts your tabular CSV rows into highly structured, compliant JSON arrays instantly.

Step-by-Step CSV to JSON Conversion

Paste your CSV: Copy and paste your tabular rows, TSV values, or spreadsheet data into the "CSV Input" editor above.
Configure Options:
- Delimiter: Set to "Auto-Detect" or explicitly select Commas, Tabs (TSV), Semicolons, or Pipes.
- First Row as Headers: Check this to use the first row of your CSV as object keys in the JSON. If unchecked, columns are given default keys (col1, col2, etc.).
- Parse Numbers: Automatically converts valid numeric strings (like 42 or 12.50) and booleans (true/false) into actual JSON types rather than strings.
Run Conversion: Click the blue "Convert to JSON" button.
Copy or Download: Copy the JSON string to your clipboard or download it as a .json file.

Advanced CSV Parsing Features Explained

Unlike basic string-splitting scripts that break when they encounter commas inside quotes or line breaks within cells, this converter implements a robust RFC 4180-compliant state machine parser:

Quoted Fields: Cells wrapped in quotes containing commas (e.g. "Johnson, Alice") are correctly parsed as a single column instead of splitting across columns.
Escaped Quotes: Handles double-quotes inside quoted fields (represented as "") and restores them to a single quote inside the final JSON string.
Multiline Rows: Correctly parses single records that span multiple lines due to line breaks inside text fields (like descriptions or addresses).
Delimiters Support: Supports standard commas, tabs (for TSV), semicolons (common in European Excel exports), and pipes (vertical bars).

Frequently Asked Questions

What is the difference between CSV and TSV?

CSV files use commas (,) as the separator between fields, whereas TSV (Tab-Separated Values) files use tabs (\t). TSV files are highly reliable for text-heavy datasets because tabs are rarely found inside standard text values, reducing the risk of parsing alignment errors. Select "Tab (TSV)" in our Delimiter menu to convert them.

How does numerical parsing work?

By default, CSV files represent all values as text. If you check "Parse Numbers", the converter will check if a field contains a valid integer, decimal, or boolean. If so, it converts the JSON value to an actual number type (e.g. "age": 30 instead of "age": "30") or boolean type, making the data ready for math operations in your code.

Can this tool parse massive CSV logs?

Yes. Because the parser runs locally using client-side JavaScript, it is incredibly fast and memory-efficient. It can parse logs containing tens of thousands of lines in milliseconds. It is limited only by your web browser's RAM and CPU capabilities.

Are my sensitive spreadsheets secure?

Yes, absolutely. Since all conversion takes place locally in your web browser, no text is sent over the internet or uploaded to our servers. Your proprietary databases, marketing lists, or logs never leave your machine, meeting strict enterprise compliance standards.

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🔒 100% Client-Side Privacy

All CSV parsing and JSON generation happens entirely in your browser. No data is ever uploaded to any server. Your data stays on your device at all times.