JSON Diff
Paste two JSON documents and see exactly what changed — added, removed, or modified keys.
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About JSON Diff
JSON Diff compares two JSON documents and shows exactly which keys were added, removed, or had their values changed. It is an indispensable tool during code reviews, API version migrations, and debugging sessions where you need to compare configuration files or API response snapshots.
Why JSON Diffing Matters
Modern applications often store configuration as JSON — think package.json, Terraform state files, AWS CloudFormation templates, and REST API payloads. When a deployment breaks something, the first question is: "what changed?" A JSON diff tool answers that instantly.
Understanding the Output Format
This tool outputs differences in a human-readable format: keys prefixed with + appear only in JSON B (added), keys prefixed with - appear only in JSON A (removed), and keys prefixed with ~ exist in both but have different values.
Common Use Cases
API versioning: Compare v1 and v2 response shapes to find breaking changes before updating client code. Config management: Diff production vs staging configuration to find environment-specific overrides. State debugging: Compare Redux store snapshots before and after an action fires to isolate bugs. Terraform / IaC: Before applying infrastructure changes, diff the plan output to catch unintended resource modifications.
Nested Object Diffing
This tool recursively walks nested objects and arrays, reporting the exact path to each changed value using dot notation (e.g., user.address.city). Array diffs show index-level changes.
Security Note
All comparison happens client-side in your browser. No JSON data is ever sent to a server, making this safe for diffing sensitive configuration containing API keys, database URLs, or private credentials.