Nested CSV to JSON Converter

How to use this tool

1. Enter your values in the labelled fields or load the worked example.
2. Review the assumptions below, then run the tool.
3. Review the result, then copy or download it.

Try this example

person.name,address.city
Ada,London
Sam,Paris

Accuracy and scope

Default output values are strings; optional inference recognizes supported booleans, null and numbers. Leading-zero identifiers and unsafe integers remain strings. Dot-separated object paths only; no array-index syntax. Conflicting or unsafe paths are rejected. Maximum 50,000 CSV rows and 200 columns.

Is my data uploaded?

This tool runs locally in your browser. Input and output are not sent to a processing server. Copy or download your result before leaving the page.

Rename columns using a JSON object, for example {"old":"new"}. Later filters and grouping use the renamed headers. Fill empty cells after trimming and empty-row removal. Row numbering is applied after sorting and selection. The column report describes retained output rows: unique counts include empty values; numeric counts exclude blanks. Automatic delimiter detection accepts exactly one consistent comma, semicolon, pipe or tab structure; select explicitly if ambiguous.