DevToolKit

CSV to JSON Converter

Convert CSV, TSV, and spreadsheet data to JSON formats including arrays of objects, arrays of arrays, and JSON lines with nested data support.

CSV Input

Conversion Options

Convert '123' to number
user.name → {user:{name:..}}

JSON Output
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How to Use

Our free online CSV to JSON converter translates comma-separated values (CSV) into structured JSON arrays instantly. It's built for developers and data analysts who need to migrate spreadsheet data into web-friendly JSON formats.

  1. Paste or Upload: Paste your raw CSV data into the left input box, or click the "Upload File" button to load a .csv or .tsv file from your device.
  2. Configure Parsing: Select your delimiter, toggle header row processing, and choose whether strings like "123" should be converted into native JSON numbers.
  3. Copy or Download: Use the "Copy" icon or the "Download JSON" button to save your formatted output.

About This Tool

This tool uses the industry-standard PapaParse engine running directly in your browser. It accurately handles edge cases that simple regex scripts fail on, such as quotes within quotes, escaped commas inside data fields, and malformed trailing spaces.

The tool can output either an Array of Objects (if "First row is header" is checked) where each row is mapped to column keys, or an Array of Arrays (if unchecked) for raw data matrices.

Why Use This Tool

100% Client-Side Privacy

Spreadsheets often contain sensitive customer or financial data. This tool processes all your data locally in your browser.

No files or text are ever uploaded to an external server, guaranteeing complete privacy and instant conversions regardless of your internet connection speed.

FAQ

Can I upload a CSV file instead of pasting?
Yes! Click the 'Upload File' button or drag and drop your .csv or .tsv file into the converter. The tool handles files up to 50MB entirely in your browser.
How does nested object transformation work?
If your CSV headers use dot notation (e.g., 'user.name', 'user.email'), you can enable 'Nested objects'. The converter will automatically nest these into sub-objects like { 'user': { 'name': '...', 'email': '...' } }.
What is the JSON Lines format used for?
JSON Lines (.jsonl) is a format where each line is a valid JSON object. It is widely used for processing large datasets in data engineering, log analysis, and database migrations (like MongoDB or BigQuery).
Is my data private?
Yes. DevToolkit uses 100% client-side processing. Your data never leaves your computer and is never sent to our servers. All conversions happen in your browser's memory.
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