ST
StringTools

CSV ↔ JSON Converter

Convert CSV to JSON and JSON to CSV instantly. Supports custom delimiters, headers, and type detection — 100% browser-based.

Why Convert Between CSV and JSON?

CSV is the universal format for tabular data — it powers Excel, Google Sheets, database exports, and legacy systems. JSON is the standard for modern APIs, web apps, and document databases. Converting between the two is one of the most common tasks in data work.

Whether you're migrating a spreadsheet into a REST API, bulk-loading records into MongoDB, or exporting JSON responses into Excel for your team, this converter handles both directions instantly — entirely in your browser.

Common Use Cases

Data Migration — Convert Excel / CSV exports into JSON for bulk import into MongoDB, Firebase, or any REST API.

API Testing — Turn CSV test fixtures into JSON request bodies for Postman, curl, or unit tests.

Reporting — Export API JSON responses to CSV for analysis in Excel, Google Sheets, or BI tools.

Analytics Pipelines — Transform between tabular and structured formats during ETL workflows.

Features

  • Two-way conversion — CSV → JSON and JSON → CSV, switchable with one click.
  • Multiple delimiters — Comma, semicolon, tab (TSV), or pipe separators.
  • Automatic type detection — Numbers, booleans, and nulls are correctly typed in JSON output.
  • Header row support — First CSV row is treated as JSON object keys.
  • Copy & download — Export as .json or .csv with one click.
  • 100% client-side — All conversion runs in your browser. Nothing is uploaded.

Frequently Asked Questions

How do I convert CSV to JSON?

Paste your CSV data into the input box. The first row is treated as headers, and each subsequent row becomes a JSON object. The result appears instantly — ready to copy or download.

How do I convert JSON to CSV?

Switch the direction to JSON → CSV, paste an array of JSON objects, and the tool converts it to CSV with headers derived from the object keys.

Does it support different delimiters?

Yes. Use the delimiter dropdown to switch between comma, semicolon, tab (TSV), and pipe-separated values.

Is my data safe?

Yes. All conversion happens 100% in your browser. Your data never leaves your device.