JSON Merge
Deep-merge multiple JSON objects into one, live as you type. Later objects override earlier ones on conflicts.
JSON object 1
JSON object 2
Merged result
No output yet
Fill in every object with valid JSON — the merged result appears here.
About the JSON Merge
A JSON merge tool combines multiple JSON objects into one. It performs a deep merge: nested objects are merged recursively rather than overwritten wholesale, which is what you usually want when layering configuration.
When the same key exists in more than one object, values from later objects win. The merge runs in your browser, so you can safely combine environment configs, feature flags, or partial API payloads without sending them anywhere.
How to use the JSON Merge
- 1Paste your first JSON object into the first input.
- 2Add more inputs and paste each additional object to merge.
- 3Click Merge — later objects override earlier ones on conflicting keys.
- 4Copy or download the combined result.
Common uses
Layering configuration
Merge a base config with environment-specific overrides into a single document.
Combining partial responses
Stitch together paginated or partial API payloads.
Applying defaults
Merge user-supplied values on top of a defaults object.
Frequently asked questions
Is this a deep or shallow merge?
Deep. Nested objects are merged recursively, so overriding one nested key does not discard its siblings.
What happens on conflicting keys?
The value from the later object in the list wins. Order your inputs from lowest to highest priority.
How are arrays handled?
Arrays are replaced by the later value rather than concatenated, which matches how most configuration systems behave.
Is my data private?
Yes. The merge is computed entirely in your browser.