Data Converter moves tabular data between the formats that tools actually use. Load a CSV and write JSON, load an XLSX sheet and write NDJSON for a log pipeline, or go the other way. Along the way you can filter to the rows you want, join a second file on a shared column, and drop duplicate rows.
The files are parsed in the page with the browser File API. Nothing is uploaded.
It reads one sheet at a time. Pick the sheet after loading the workbook.
Each row becomes an object keyed by the header names. NDJSON writes one such object per line; JSON writes an array.
An inner or left join on a single key column. Rows with no match are kept or dropped depending on the setting.
No. Parsing, joining, and conversion all run in the tab.
Files up to a few hundred thousand rows are fine on a typical machine. The whole file is held in memory.