CSV ↔ JSON Converter

The CSV to JSON Converter is a free, browser-based utility that transforms data between CSV (Comma-Separated Values) and JSON (JavaScript Object Notation) formats in real time. Whether you are preparing data for a REST API, importing spreadsheet exports into a JavaScript application, or converting API responses into a tabular format for analysis, this tool handles the conversion instantly without any server involvement.

CSV is the most widely used format for tabular data exchange. It is supported by every spreadsheet application, database export tool, and data pipeline. JSON, on the other hand, is the standard for web APIs and modern application configuration. Converting between these two formats is one of the most common tasks developers and data analysts face daily, and doing it manually is tedious and error-prone.

This tool implements an RFC 4180 compliant CSV parser built from scratch. It correctly handles quoted fields, escaped double quotes, newlines embedded within quoted fields, and various delimiter characters including commas, semicolons, tabs, and pipes. You can toggle whether the first row of your CSV should be treated as column headers, and control whether header rows are included in CSV output.

All processing happens entirely in your browser using native JavaScript. Your data never leaves your machine — there are no server round-trips, no logging, and no third-party services involved. This makes it safe to convert files containing customer data, financial records, or any other sensitive information. The built-in preview table shows the first 10 rows of your parsed data, giving you immediate visual confirmation that the conversion is correct before you copy or download the result.

1. Select the conversion direction using the CSV → JSON or JSON → CSV toggle at the top.
2. Paste your data into the Input panel, or drag and drop a .csv or .json file onto the panel. The file type is auto-detected.
3. Choose a delimiter (comma, semicolon, tab, or pipe) from the options bar. For CSV input, toggle the First row is header checkbox to control whether the first row becomes JSON keys.
4. The converted output appears instantly in the Output panel, and a preview table shows the first 10 rows of the parsed data below.
5. Click Copy to copy the output to your clipboard, or Download to save it as a file.
6. Use the Swap button to reverse the direction and move the current output into the input.
7. Click Clear to reset the tool.