JSON Flatten

nested → flat · dot or bracket keys

Flatten nested JSON to a single-level object with dot-notation or bracket-notation keys. Reverse direction at JSON unflatten. Useful for config systems that don't support nesting.

Key style Flatten arrays too (items.0.id)

Input JSON

Flat output

Paste JSON.

How to flatten

Paste your JSON in either panel.
Configure Style: Dot (user.address.city), Bracket (user[address][city]), or Custom delimiter.
Toggle Flatten arrays — on (items.0.id) or off (arrays kept whole).
The opposite panel updates live. Copy or Download.

FAQ

What if my keys contain dots already?

The output is ambiguous — switch to Bracket style or use a custom delimiter that doesn't appear in your keys.

How is this different from json-to-csv?

json-to-csv does this same flatten as part of building a CSV. Use json-flatten when you want the flat JSON itself, not a CSV.

Will it work offline?

Yes.