JSON Flatten / Unflatten — Dot Notation Converter

What is JSON Flatten?

A flat JSON representation collapses every nested object and array into a single-level map where each key is the full path (like `user.address.city` or `items[0].name`) and each value is the leaf. It's the natural format for exporting JSON to spreadsheets, storing settings in a key/value backend (Vault, Redis, Spring @ConfigurationProperties), diffing two JSON documents by field, and feeding search engines that don't support nested queries. This tool converts in both directions and supports the two industry-standard array notations: bracket (Postman / JSONPath) and dot (lodash / Spring).

How to flatten and unflatten JSON

1. 1Choose direction — Flatten (nested → flat) or Unflatten (flat → nested).
2. 2Choose an array style: bracket (a[0].b) for JSONPath / Postman compatibility, or dot (a.0.b) for lodash / Spring.
3. 3Paste your JSON. The output pane instantly renders the converted form.
4. 4Copy the result. Keys containing the delimiter character are auto-wrapped in backticks so round-tripping stays lossless.

Tips & Best Practices

• ▸For CSV export, flatten first — one column per path — so every row is a rectangular record.
• ▸When your target is Spring @Value / configuration properties, choose dot-array style and switch the delimiter to match the framework's expectation (usually '.').
• ▸Empty objects and arrays are encoded as {} and [] sentinel keys so structure survives the round trip — don't strip them if you plan to unflatten.