Clean a CSV and split it for import

Choose duplicate keys, preserve text codes and split a reviewed table into smaller CSV files.

Keep the original CSV and work on a copy. Decide what one record means and which columns identify a duplicate before removing anything.

1. Inspect headers and preview changes

   Use unique, nonempty headers. Choose trimming, blank-row removal and duplicate keys. Two records sharing a name are not necessarily duplicates; preview the retained first occurrence.

   Open CSV cleaner & deduplicator

2. Choose an import-friendly split

   Split by record count for an importer’s row limit or by an exact column value for separate groups. Headers repeat in every output. Clean inconsistent group names first.

   Open CSV splitter & column extractor

3. Convert only when the destination needs JSON

   Convert a smaller reviewed CSV into objects. Values stay strings, so 00123 remains a code. Assign numeric types deliberately in the destination application.

   Open CSV to JSON converter

name,email
Ada,[email protected]
Ada,[email protected]
Sam,[email protected]

After exact all-column deduplication: two records, Ada and Sam. Splitting at one record produces two CSV files, each with a header.

Check before you finish

CSV cleaner/splitter accept up to 20 MB, 200,000 rows, 200 columns and two million cells. Splits stop at 100 files / 60 MB. Spreadsheet formula protection adds an apostrophe to sensitive prefixes; review the effect on legitimate negative numbers. Neither export overwrites the source.

How files, backups and tool handoffs are handled