JSON Flattener
Flatten nested JSON into a single level of dot-notation keys.
Collapsing the nesting
Deeply nested JSON is precise but awkward for some tools — spreadsheets, certain databases, flat config formats — that expect a single level of keys. Flattening collapses the nesting into one level, joining the path to each value with dots, so a nested field becomes a key like user.address.city. This turns a nested document into a flat set of key-value pairs.
Paste nested JSON and it is flattened.
Where flattening helps
The flat form shines when you need to map JSON onto something that is not hierarchical: turning records into spreadsheet columns, feeding a flat key-value store, or diffing two documents field by field. Arrays are usually flattened by index, so each element gets its own indexed key. The process is reversible in principle — the dotted keys record the original structure — so flattening for one purpose does not lose the shape, it just presents it differently.
Common questions
How are nested keys represented?
By joining the path with dots, so a nested field becomes a key like user.address.city, with arrays flattened by index.
When is flattening useful?
When mapping JSON onto flat structures — spreadsheet columns, key-value stores — or diffing documents field by field.
Is my JSON uploaded?
No. The flattening happens in your browser.