Merge rulesDeep-merge B into A: same-name objects merge recursively, B scalars override A; arrays follow the chosen strategy (replace / concat / by index).

Two JSONs

ABase A

BOverride B

Load both A and B

Merged

Merged output will appear here

Deep-merge two JSONs

JSON Merge

Deep-merge A and B · B overrides A · array strategy · local

🔒Processed locally in your browser — never uploaded or stored

No upload, no storage

JSON is processed in memory and never sent to a server.

Share via URL fragment

Share links encode data in the # anchor — never sent to a server.

Remember last edit

Optionally keep your last input locally; clear it with one click.

Why use JSON Merge

Deep merge

Recursively merge same-name objects of two JSONs instead of a shallow whole-value overwrite.

B overrides A

On conflict, B wins — perfect for overlaying a patch onto a base config.

Array strategy

Same-name arrays can replace, concat, or merge element-by-element — not just one default.

Merge configs / patches

Great for merging default and env configs, or base data with incremental patches.

Local · no upload

Everything runs in your browser; data is never uploaded or stored.