JSON to CSV Converter — Flatten JSON to Spreadsheet

This free JSON to CSV converter turns JSON data into a flat, spreadsheet-ready CSV file. It flattens nested objects into dotted column headers and maps arrays of objects to rows, handling the escaping rules that prevent corruption — any value containing a comma, quote, or newline is wrapped in double quotes per RFC 4180. The result opens cleanly in Excel or Google Sheets. Because the conversion runs entirely in your browser, your data is never uploaded, so you can convert sensitive exports safely.

CSV output will appear here...

✨ Pro Tips for Best Results

  • Arrays Work Best: This tool is optimized for arrays of objects (e.g. [{...}, {...}]).
  • Flattening: Nested objects will be flattened using dot notation (e.g. user.name).
  • Data Privacy: Your JSON is never sent to a server. Conversion happens entirely on your device.

How JSON to CSV conversion works

JSON to CSV conversion is the process of taking hierarchical data (JSON) and mapping it into a tabular format (Comma Separated Values). This is essential for data analysts who need to move data from modern web APIs into spreadsheet software like Excel or SQL databases.

Our converter works by first parsing your JSON string. It then identifies all unique keys across all objects in an array to create the header row. For every subsequent object, it maps values to their respective columns. If an object is missing a key, the cell is left empty. If a key contains a nested object, the tool recursively flattens it so no data is lost. All of this logic is executed in JavaScript within your browser session, ensuring that sensitive data never touches an external server.

Flattening nested structures

CSV is a flat grid; JSON is a tree. Converting between them means deciding how to flatten nested objects and arrays. A common convention turns {"user":{"name":"Sam"}} into a column header user.name. Arrays of objects usually become one row each, while arrays of scalars are often joined into a single delimited cell — there is no one right answer, so consistency across rows matters most.

Escaping rules that prevent corruption

Any field containing a comma, a double quote or a newline must be wrapped in double quotes, and literal quotes inside are doubled (" becomes ""). Skip this and a single address with a comma will silently shift every later column — the most common cause of "my spreadsheet import is misaligned".

Headers and encoding

Derive column headers from the union of all object keys so rows with missing fields still align, leaving blanks where data is absent. Save as UTF-8, and add a byte-order mark if the file must open cleanly in older versions of Excel, which otherwise mangle accented characters.

⚠️ Common Mistakes to Avoid

Frequently asked questions

Can I convert large JSON files?

Yes, our tool processes the data locally in your browser for speed and privacy.

Does it support nested JSON?

The tool attempts to flatten simple nesting, but for very complex structures, data may be simplified.

Related guides

JSON vs XML → API Payload Optimization →
Reviewed by the ToolsmithPro editorial team · Last updated June 2026. Every calculation and conversion runs entirely in your browser — your inputs are never uploaded, stored or shared. Formulas and methodology are documented on our about page; spot an error? tell us and we'll fix it.

Related tools

JSON formatter → Text diff → Remove duplicates →