JSON Flatten / Unflatten
Dotted keys · Arrays as 0.1.2 · Local
YAML Conversion
Ready
ABOUT
About JSON Flatten / Unflatten
Turn nested objects and arrays into a single flat object whose keys are paths, then restore the tree. Default separator is a dot; underscore is optional.
The Query params tool still converts URL query strings. This page never emits a=1&b=2.
DEEP DIVE
JSON Flatten / Unflatten
Spreadsheets, Elasticsearch, and some log pipelines prefer flat maps. Developers still want the nested document for APIs.
Array indexes become numeric path segments: user.tags.0. Empty objects and arrays are kept when they have a path.
FEATURES
JSON Flatten / Unflatten
Flatten
Nested JSON → {"user.profile.age": 31}.
Unflatten
Dotted keys → nested objects and arrays.
Separator
Dot or underscore.
Local only
No upload.
Not Query convert
a=1&b=2 stays on the Query page.
Works after JSONL
Flatten each object from an NDJSON array.
HOW TO USE
How to use
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1
Paste nested JSON (or a flat object).
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2
Choose Flatten or Unflatten.
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3
Optionally switch the separator.
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4
Copy the result.
FAQ
FAQ
Is this the Query converter?
No. Query is for URL search strings. This page is a JSON object with path keys.
How are arrays encoded?
Numeric segments: items.0.name.
What if a key already contains a dot?
Treat keys as atomic only after split; avoid dots inside original keys or pick underscore.
Can I flatten a root array?
Yes. Keys start at 0, 1, 2.
Is data uploaded?
No.
Does CSV export stay on the CSV page?
Yes. This page does not build tables.