How to use JSON diff & merge
Paste your first JSON object into the left panel and your second into the right panel.
Choose Diff mode to inspect changes, or Merge mode to combine both objects.
Run the tool, then copy or download the result once it looks right.
When to use each mode
Diff - compare payloads
See exactly which keys changed, were added, or were removed between two API responses or config snapshots.
Diff - debug environments
Compare staging vs production config files to find the specific value causing a difference in behavior.
Merge - combine configs
Merge a base config with an override file, choosing which side wins when both have the same key.
Merge - consolidate data
Combine two partial API responses or fixture objects into a single complete JSON result.
Why this helps in real workflows
You want to compare two API payloads or config snapshots.
You need a quick merged JSON result from two objects.
You are debugging why one environment config differs from another.
You want readable path-level differences without diffing by hand.
Related Guides
Frequently asked questions
How does the diff work?
The diff compares both JSON objects at the path level. It reports which keys were added, removed, or changed, including nested paths like user.address.city.
What does "right side wins" mean in merge mode?
When both objects have the same key with different values, "right side wins" means the value from the right panel is used in the merged result. "Left side wins" does the opposite.
Does this tool handle nested JSON?
Yes. Both diff and merge work recursively on nested objects and arrays.
Is this JSON diff and merge tool free?
Yes. It is completely free, no account required, and it runs entirely in your browser.