JSON Diff
Compare two JSON objects and see exactly what changed — added, removed or modified.
Compare JSON Objects to Track API Changes and Debug
APIs evolve over time — response structures change, new fields are added, deprecated fields are removed. When a bug appears after an API update, you need to quickly identify what changed between the old and new response. Our JSON Diff tool flattens nested objects using dot notation (e.g., user.address.city) and shows added, removed and changed key-value pairs in colour-coded output, making differences immediately obvious.
Frequently Asked Questions
How to compare two JSON files for differences? ▼
Paste JSON Object A (original) in the left box and JSON Object B (modified) in the right box, then click Compare. Added keys show in green, removed in red, changed values in yellow. The summary shows exact counts of added, removed and changed fields.
What is JSON diff used for in software development? ▼
Common uses: (1) Comparing API responses before and after a deployment, (2) Reviewing config file changes in pull requests, (3) Debugging data transformation pipelines, (4) Comparing feature flag configurations, (5) Validating that a refactored function produces identical output.
How to compare nested JSON objects? ▼
Our diff tool flattens nested JSON using dot notation before comparing. So {"user":{"name":"Alice","age":30}} becomes user.name: "Alice" and user.age: 30 — making deeply nested differences visible at a glance rather than requiring manual traversal of nested objects.
What is the best JSON diff tool online? ▼
SecuredTools JSON Diff is completely free, client-side (your data never leaves your browser) and handles nested objects via dot-notation flattening. Other options include jsondiff.com and diffchecker.com — but those may upload your data to servers.