JSON rename keys

Client

Map old property names to new ones—deep rename walks every nested object by default. Paste JSON and your rename lines; copy the transformed document locally.

Learn more: renaming property names

Apply a line-based old → new map to object keys—deep mode walks nested objects and objects inside arrays.

Collisions

If the new name already exists on an object, the renamed value overwrites the previous one. Review output when maps could target the same destination key.

Arrays

Array indices are unchanged. Renaming applies to keys on objects within arrays when deep rename is enabled.

Rename keys

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One mapping per line: old -> new, old = new, or old, new. Lines starting with # are ignored. When a new name collides with an existing key, the renamed value wins.

Renamed 4 keys.

Nearby workflows on Toolcore

Common use cases

  • Align legacy API field names (token) with new schema names (access_token) in sample fixtures.
  • Batch-rename keys in exported config before converting to another format or language codegen.
  • Normalize snake_case to camelCase in nested objects when only key names—not values—must change.
  • Prepare anonymized copies where identifiers move to neutral names without restructuring values.

Common mistakes to avoid

  • Expecting value transforms

    Only property names change. To mask secret values, use redact keys; to drop fields, use pick/omit.

  • Colliding new names silently overwriting data

    When a renamed key already exists, the renamed value wins. Review the output when maps could overlap.

  • Renaming array elements

    Arrays keep numeric indices. Renaming applies to object keys inside arrays when deep rename is on.

FAQ

What map formats are supported?

One mapping per line: old -> new, old = new, or old, new. Lines starting with # are ignored.

Can I rename only top-level keys?

Turn off “Rename at every object level” to affect only the root object (or each object in a root array).

Is processing local?

Yes. Parsing and renaming happen in your browser tab.

Common search terms

Phrases people search for that match this tool. See the full long-tail keyword index.

  • rename json keys online
  • json key rename tool
  • change json property names

More tools

Related utilities you can open in another tab—mostly client-side.