Extract Unique Values from Parquet Files Online

What is the difference between unique-values and count-by for Parquet files?

Unique values returns a list of distinct values with no frequency information. Count-by adds a row count for each value. Use unique values when you need the list itself — for example to populate a dropdown or check what categories exist.

Can I extract unique values from multiple columns of a Parquet file?

One column at a time. The output is a single-column file of distinct values ready to download.

How many unique values can the tool extract from a Parquet file?

There is no limit. The tool computes distinct values across the full dataset regardless of file size, within your device's available RAM.

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.