Clean — by Similarity API
Free JSON to CSV Converter
Convert JSON to CSV in your browser. Flatten nested objects, select a row path, choose columns and preview before downloading. Free, no upload.
Your data never leaves your browser
How it works
Three steps. One clean result.
Step 1
Add JSON
Open a JSON file or paste your data.
Step 2
Choose your records
Select a nested row path if needed, flatten objects and choose output columns.
Step 3
Download CSV
Check the table preview, choose a separator and download all selected fields.
Why Clean
The details that make a difference
Nested objects
Dotted column names such as address.city retain the structure of nested fields.
Arrays stay intact
Arrays are serialized inside a cell, not silently expanded into extra rows.
No lost false or zero
False and zero are preserved. Null and missing fields become empty cells.
Before
[{"name":"Ada","address":{"city":"London"},"active":false}]After
name,address.city,active Ada,London,false
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Frequently asked questions
Is this tool free?
Yes. Clean is free, with no account, payment or download gate.
Is my data uploaded?
No. Processing happens in your browser. Your input is not sent to our servers, sold, shared or used for AI training. Large inputs are limited by your device’s available memory.
Which JSON structures work?
Arrays of objects, single objects, arrays of arrays and primitive lists are supported. Primitive values use a value column; arrays of arrays use generated column names.
What is a row path?
A dot-separated path such as data.results selects records inside an API response. Keys containing literal dots cannot be selected with this path notation.
How are nested arrays handled?
Arrays stay as JSON text inside a cell. Nested objects are flattened when enabled; disabling flattening keeps objects as JSON text too.
What if JSON is invalid?
Conversion is blocked and a parsing error is shown. Flattened-key collisions are also blocked rather than overwriting values.