Extract JSON Column from CSV Files Online

What is a JSON path and how do I write one for a CSV file column?

A JSON path is a dot-notation expression that locates a value inside a JSON string. Start with $ for the root. Use $.fieldName to access a top-level key, $.nested.field for a nested key, and $.array[0] for the first element of an array. For example, if a column contains {"user":{"email":"a@b.com"}}, the path $.user.email extracts the email.

What if the JSON path doesn't exist in some rows of my CSV file?

Rows where the path does not exist, or where the column value is not valid JSON, will have NULL in the extracted column. This is safe — no errors are thrown for missing paths.

Can I extract multiple JSON fields from the same column in a CSV file?

This tool extracts one path at a time. Run the tool multiple times with different paths, saving and re-loading the result each time. Alternatively, use the SQL Query tool and write SELECT *, json_extract_string("col", '$.field1') AS field1, json_extract_string("col", '$.field2') AS field2 FROM your_table.

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.