JSON Flattener
Flatten deeply nested JSON into a single-level object with dot-notation keys. Runs entirely in your browser.
Pure browser JavaScript — no external libraries.
How to use this tool
- Paste JSON or upload a .json file.
- Choose the key separator (default '.') and whether to index array items.
- Click Flatten, then Copy or Download the flat JSON.
Flatten deeply nested JSON into a single-level object with dot-notation keys. Runs entirely in your browser.
Frequently asked questions
- How are arrays handled?
- With 'Index array items' on, each element gets a numeric segment (e.g. roles.0, roles.1). Turn it off to keep array values under the parent key.
- Is anything uploaded?
- No — flattening runs entirely in your browser.