Structured Data
CSV and JSON Converter
Move a flat tabular fixture between CSV/TSV and JSON array-of-objects formats.
How this tool works
CSV input uses its first row as unique column names. JSON input uses the sorted union of object keys for deterministic columns and quotes delimiters and line breaks.
CSV cells are strings; null and missing JSON values become empty cells. Nested JSON objects and arrays are rejected instead of silently flattened.
Examples
- Convert a two-column fixture to JSON.
- Quote a field with a newline.
- Reject duplicate headers rather than overwrite data.
Common use cases
Build a small flat JSON fixture from a spreadsheet export.
Worked synthetic example
Valid example
id,name 7,Ada
Expected: [{"id":"7","name":"Ada"}]. CSV cell values remain strings in JSON.
Failure or warning to recognize
Invalid/failure example
CSV with duplicate id,id column headers.
Expected: Duplicate CSV headers such as id,id report an error instead of overwriting one column.