CSV to JSON Converter Online — Convert CSV and JSON

Convert CSV to JSON or JSON to CSV online in your browser. Transform tabular data locally with quoted-cell and header support.

About this tool

This CSV and JSON converter treats the first CSV row as object keys and converts following rows into a JSON array. When input starts with a JSON array, it builds a CSV header from all object keys and escapes commas, quotes and line breaks.

How to use

Paste CSV with a header row, or paste a JSON array of objects.
Run the converter; CSV becomes formatted JSON and a JSON array becomes CSV.
Review column names, empty cells and value types before copying the result.

Features

Uses the first CSV row as JSON property names.
Handles quoted commas, quotes and line breaks in CSV cells.
Combines object keys into a shared CSV header.

Common use cases

Prepare spreadsheet exports for an API or script.
Create CSV rows from a JSON array of records.
Inspect tabular data as readable structured JSON.

Common issues and tips

CSV values are returned as strings and are not automatically converted to numbers or booleans.
JSON-to-CSV input must be an array of objects; nested values do not map cleanly to flat cells.

Privacy

CSV and JSON conversion runs locally in your browser. The data you enter is not uploaded to Tools12345.

Frequently asked questions

Does the first CSV row become JSON keys?

Yes. Each first-row cell is used as the property name for values in the corresponding column.

Can CSV cells contain commas?

Yes. Values containing commas, quotes or line breaks should use standard double-quoted CSV escaping.

What JSON shape is required for CSV output?

Use an array of objects. The converter collects their keys to build the CSV columns.