Free Online CSV to JSON Converter & JSON to CSV – Convert Spreadsheet Data with Table Preview

CSV & JSON Converter

Convert CSV to JSON or JSON to CSV, preview it as a table, and download the result • 100% free • No upload to server

1. Direction & file

Convert CSV to JSON JSON to CSV Open a file (.csv, .tsv, .json, .txt - up to 10 MB)

The file is read in your browser and never uploaded.

2. CSV reading options

Delimiter in your CSV Auto-detect Comma , Semicolon ; Tab Pipe | First row contains column names Trim spaces around values Skip empty rows

3. JSON output options

Structure Array of objects (most common) Array of arrays Object keyed by first column One object per line (NDJSON) Formatting Pretty, 2 spaces Pretty, 4 spaces Pretty, tabs Minified Convert numbers, true/false and null Empty cells become null

Values with leading zeros (like 0123) and very long numbers stay as text so nothing is lost.

2. CSV writing options

Delimiter for the CSV Comma , Semicolon ; (Excel in many countries) Tab (TSV) Pipe | Line endings LF (Mac, Linux, web) CRLF (Windows, Excel) Include a header row Put quotes around every value

3. Nested data & safety

Flatten nested objects (address.city) Lists inside a record Join simple lists with ; Keep as JSON text Add a BOM when downloading (helps Excel read UTF-8) Protect against spreadsheet formula injection

Protection adds an apostrophe before text starting with = + @ or -, so a spreadsheet will not run it as a formula.

CSV input

JSON output

Table preview

Everything runs in your browser. Your data is never uploaded.