Transform JSON and CSV on your device
Keep text local while preserving numeric precision and controlling spreadsheet behavior.
Use the local workspace
JSON to CSV, CSV to JSON, JSON formatter, and text encoding run in a browser worker. Choose a file or paste text. The content is never automatically uploaded, and the maximum size is 5 MB.
Choose types and nested values explicitly
CSV to JSON preserves strings by default, so leading zeros stay intact. Typed conversion is optional. JSON to CSV can reject nested values or serialize them as JSON. Large integer and decimal tokens preserve their original numeric precision.
Download before closing the tab
Local results are not stored. Use spreadsheet-safe export when opening untrusted CSV in a spreadsheet; it prefixes potential formula cells explicitly. Literal export leaves the data unchanged. Text encoding rejects characters that the requested target encoding cannot represent.