How to convert csv to nested json grouped by column
- Step 1Identify the grouping column — Pick the CSV column whose values define the groups — for example category, ownerId, or region.
- Step 2Drop the CSV onto the converter — The header row is parsed and the grouping column is offered in a dropdown.
- Step 3Pick 'grouped by column' as the output mode — Select the column from the dropdown to use as the parent key.
- Step 4Download the nested JSON — Each unique value becomes a top-level key with an array of records below it.
Frequently asked questions
What happens to rows with empty values in the grouping column?+
They are placed under the _unknown key. Rename it after download if you need a custom bucket label.
Can I produce multi-level nesting?+
This pass produces one level. For deeper structures, run two passes: first group on the outer key, then post-process the JSON in code.
Is the grouping case-sensitive?+
Yes. "Books" and "books" become different groups. Run the CSV Case Converter beforehand to normalise the values if needed.
Privacy first
Conversion runs locally in your browser. No file is uploaded — only metadata counters are saved for signed-in dashboard stats.