JSON Key Renamer
Rename keys across a JSON object.
Rename JSON keys in bulk
Renaming a field throughout a payload by hand is error-prone. This renames a key everywhere it appears, including inside nested objects and arrays, in one pass.
It is the safe way to rename a field across a whole payload — following an API change or a schema tidy-up — without the risk of a find-and-replace catching a value by accident.
Structure preserved
Only the key names change; values and nesting stay intact. The rename runs entirely in your browser. Your data is renamed on your device and never uploaded.
Frequently asked questions
What does this json key renamer do?
Rename keys throughout nested JSON using a mapping list.
How do I write the mappings?
One per line as "oldKey => newKey". Keys not in the list keep their names.
Are nested keys renamed too?
Yes. Every object at every depth, including objects inside arrays, is checked, so one mapping renames the key everywhere it appears.
Can I rename only one nested path?
No. Matching is by key name, not by path, so "id => user_id" renames every id. Rename that part separately if other ids must stay unchanged.
Related tools
More free browser utilities for data cleanup, formatting, and developer workflows.