Count Values in NDJSON Files Online

What does the count-by tool do with a NDJSON file?

It groups rows by the unique values in a chosen column and counts how many rows fall into each group — equivalent to SELECT col, COUNT(*) FROM table GROUP BY col ORDER BY count DESC.

Can I count by multiple columns in a NDJSON file?

This tool counts by one column at a time. For multi-column grouping use the SQL Query tool or the Aggregate tool, which supports GROUP BY on multiple columns.

How are results sorted in the NDJSON count-by output?

Results are sorted by count descending by default, so the most frequent values appear first. You can re-sort the output using the Sort tool.

Is my data private?

Yes — completely. Your file is never uploaded to any server. Everything runs locally in your browser using WebAssembly — processing happens entirely inside your tab. Once you close the tab, nothing is retained.

What is the maximum file size?

The free limit is 50 MB. For larger files, performance depends on your device's available memory — most modern machines handle 500 MB to 1 GB comfortably.