CSV Null Value Profiler

How to use this developer tool

1. Paste the CSV input or load a local file.
2. Choose the options that match the source format.
3. Select Profile Null Values or press Ctrl/Cmd + Enter.
4. Review the summary and export the output you need.

What this developer tool does

This page classifies empty cells and configurable token values as null, then calculates per-column counts and percentages. The main output is ready to copy, while the structured exports retain the diagnostic fields used in the summary.

The profiler does not decide whether zero, false, or whitespace should be treated as missing unless you add those tokens.

Example

Input

id,name,age,city
1,Ada,36,London
2,NULL,,Paris
3,Sam,N/A,
4,,42,Seoul

Running the sample produces a tool-specific report in the output panel, with counts that correspond to the parsed records or nodes.

Use cases

• Check incoming CSV before an import or migration.
• Create repeatable fixtures for parser and ETL tests.
• Inspect structure without installing a command-line package.
• Export a compact report for code review or issue tracking.

Tips for reliable output

• Keep an untouched copy of the source before transforming it.
• Test one representative edge case as well as the happy path.
• Review quoted fields, Unicode, and empty values explicitly.
• Use the JSON export when another program will consume the report.
• Re-run the tool after changing any parsing option.

Processing details

Token matching trims surrounding whitespace and can ignore case. Missing trailing cells are counted as empty values for their header columns. Processing time is measured in the browser and the original input is left unchanged.

The profiler does not decide whether zero, false, or whitespace should be treated as missing unless you add those tokens.