JSON Merge Tool

Combine two JSON files into one. Nested objects merge automatically — nothing leaves your browser.

Merge

How it works

What does "merge" mean here?

Matching keys are combined recursively. If both files have an object at the same key, their contents are merged together instead of one replacing the other.

What happens when both files have the same key?

File B's value wins for plain values and arrays. Only nested objects are merged deeper rather than overwritten.

Is my data uploaded anywhere?

No. Everything runs locally in your browser using JavaScript. Your JSON is never sent to a server or stored.

Can I merge more than two files at once?

Not yet — this first version supports two files. Support for merging multiple files is planned.