CSV ↔ JSON Converter - Flat and Nested Data Converter
Convert CSV to JSON and JSON to CSV instantly. Support for nested flattening, custom delimiters, and smart type parsing completely in-browser.
Convert database dumps or Excel exports between CSV and JSON formats in real-time. This utility handles standard RFC 4180 CSV specifications, including field escaping, multi-line quoted values, and automatic delimiter detection (comma, semicolon, tab, pipe). On the JSON side, it supports array of objects structures and can automatically flatten deeply nested JSON trees into a single-level dotted column key format, making it incredibly easy to feed into spreadsheet programs like Microsoft Excel or Google Sheets.
How to use
- 1
Choose conversion direction
Click the Swap button or switch the layout header to select CSV → JSON or JSON → CSV.
- 2
Input your data
Paste your raw text into the input panel, or drag and drop a .csv/.json file directly into the editor.
- 3
Adjust settings
Open the Settings menu to toggle header detection, smart type inference, flatten nested JSON, or customize delimiters.
- 4
Copy or download
Click the Copy button to save the result to your clipboard, or click Download to save it as a local file.
FAQ
Q.Is my data secure when using this converter?
Absolutely. All parsing, serialization, and conversion happen locally inside your web browser. No data is sent to our servers, keeping your sensitive information completely private.
Q.How does the 'Smart Type Inference' option work?
By default, CSV values are parsed as strings. When enabled, smart type inference dynamically detects and converts values like '123' to integers, '12.3' to floats, 'true'/'false' to booleans, and empty cells to null values instead of empty strings.
Q.What is 'Flatten Nested JSON' used for?
JSON can hold multi-level nested objects (e.g. { 'user': { 'name': 'Alice' } }). CSV is inherently flat. The flatten option converts nested objects into single-level dot-separated columns (e.g. 'user.name': 'Alice') so that it maps cleanly to spreadsheet rows.
Q.Does this tool support custom delimiters?
Yes. It supports comma (,), semicolon (;), tab (\t), and pipe (|). You can either select 'Auto-detect' to let our parser analyze the structure, or manually lock a delimiter in the Settings dropdown.
Q.Can I parse large files?
Yes, you can drag and drop your physical .csv or .json files straight into the browser window. The file is read directly in-browser using standard HTML5 FileReader APIs, meaning even larger files process instantly without network bandwidth costs.