What does flattening a JSON object mean, and why would I do it?

Flattening a JSON object converts a deeply nested structure into a single-level object where each key is a dot-notation path to the original value. For example, {"user":{"address":{"city":"Rome"}}} becomes {"user.address.city":"Rome"}. This is useful for loading JSON into a spreadsheet (CSV), indexing into a search engine, or processing in a flat relational database.

How are nested keys represented after flattening?

Keys are joined with dots: {"a":{"b":{"c":1}}} becomes {"a.b.c":1}. Array elements use their index: {"items":["x","y"]} becomes {"items.0":"x","items.1":"y"}. This matches the convention used by Lodash's _.get() path syntax.

Does JSON flatten handle arrays inside the JSON?

Yes. Array elements are flattened using their numeric index as the key component (items.0, items.1, etc.). Nested arrays are recursively flattened in the same way.

Is JSON flatten useful for converting to CSV?

Yes — it is actually one of the most common workflows. Use JSON Flatten first to make every value a top-level key, then use JSON to CSV to convert the flattened JSON into a spreadsheet with one column per key.

Is the JSON flatten tool free and private?

Yes — completely free, no account, and runs in your browser.

JSON flat

JSON Flatten

Flatten nested JSON objects into a single-level structure with dot-notation keys.

Your files are processed locally and never uploaded to our servers.

How it works

1
Upload your file
Drop your file or click to browse. No size limit.
2
Convert instantly
Processed in your browser — nothing is uploaded to any server.
3
Download the result
Your converted file is ready in seconds.

Frequently Asked Questions

Related tools

JSON to CSV Converter

JSON → CSV

JSON Formatter & Validator

JSON format

Explore all of Askerium's free tools

Convert, analyze and transform your data directly in the browser — nothing uploaded to servers, no sign-up required.

Explore free tools