How are arrays flattened?

By default array items use the delimiter and a numeric index (roles.0, roles.1). Enable bracket notation to get roles[0], roles[1] instead, which round-trips cleanly with most unflatten tools.

What happens to empty objects and arrays?

An empty object or empty array is kept as a leaf value at its path rather than being dropped, so the structure can be reconstructed faithfully.

Is my JSON uploaded anywhere?

No. Flattening runs entirely in your browser as JavaScript. Your JSON is never sent to a server.

JSON Flattener

Flatten nested JSON into single-level dot-path keys — in your browser.

JSON flattener

Paste a nested JSON object or array and get back a single-level object where every leaf value is keyed by its full path. Object keys are joined by a delimiter you choose (a dot by default) and array items use either dot indices (roles.0) or bracket indices (roles[0]).

This is handy for diffing configs, building .env files or feeding flat key/value stores. Everything runs in your browser — your JSON never leaves your device.