JSON Merge
Deep-merge two JSON objects.
Combine two JSON objects
This deep-merges two objects, so nested structures combine rather than one wholesale replacing the other. Where both define the same key, the second wins — useful for layering config over defaults.
It is how you layer configuration: start with defaults, merge an environment-specific object on top, and let the second object override only the keys it defines.
Know the precedence
Arrays are replaced, not concatenated, which is the usual convention. The merge runs in your browser and nothing is uploaded. Your objects are merged on your device and never uploaded.
Frequently asked questions
What does this json merge do?
Deep-merge two JSON objects and inspect the combined output.
How do I enter the two objects?
Paste the first JSON object, a line containing only ---, then the second object. Values from the second object win when both have the same key.
How are nested objects merged?
Recursively. If both sides have an object under the same key, their keys are combined at each level instead of the second replacing the first.
What does the array option change?
With it off, an array in the second object replaces the first. With it on, the two arrays are concatenated, first then second.
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