How to use CSV ↔ JSON
- Select CSV to JSON or JSON to CSV, then paste input or open a file.
- Set the CSV delimiter. For JSON input, use a non-empty array of objects.
- Run conversion and check identifiers, empty cells and nested data before exporting.
Keep postal codes and multiline notes
2 records. Postal codes stay strings; a comma and a line break stay inside their notes cells.
Load this exact example ↗What changes—and what stays
CSV cells stay strings. JSON to CSV uses the union of object keys and places nested values in JSON-encoded cells. Null and missing values both become empty cells. Spreadsheet protection prefixes formula-like strings with an apostrophe.
Practical limits
Up to 1 MiB per input, 80 nested levels and 50,000 structured values. CSV supports 10,000 data rows and 200 columns. JSON comparison returns at most 5,000 differences. UTF-8 files only; large jobs stop after six seconds.
Common questions
Why are numbers inside quotes?
CSV has no built-in type schema. Keeping every cell as a string preserves identifiers, leading zeros and empty values.
Is a round trip lossless?
Not for every JSON value. CSV export merges null and missing cells and encodes nested structures as text. Review the destination format before replacing your source.