A

Online CSV & JSON Converter

Convert between CSV and JSON with custom delimiters and header control. 100% private, all processing in your browser

Copied
Ctrl/⌘+EnterCopy resultCtrl/⌘+SDownload resultCtrl/⌘+Shift+XSwap input/output

Frequently Asked Questions

In CSV to JSON mode, each row becomes an object keyed by the header row (or by column index). In JSON to CSV mode, an array of objects is serialized into rows with the object keys as the header.

No. All conversion is done locally in your browser. Your data never leaves your device, fully protecting your privacy.

Comma (,), semicolon (;), tab, and pipe (|). Pick the one that matches your data, common in European spreadsheets that use semicolons.

When enabled, the first CSV row (or JSON object keys) is treated as field names. Disable it to use generic column names like col1, col2 for headerless data.

Completely free. This is a pure frontend online tool - no registration required, no payment needed, just open and use.

For JSON to CSV, provide an array of objects (or a single object). Nested objects and arrays are stringified into a single cell, while top-level keys become columns.