How to Compare JSON Online — Find Key and Value Differences
Spot added keys, removed fields, and changed values between two JSON documents instantly with a free browser-based diff tool.
Comparing JSON by eye is painful once documents grow beyond a few lines. Whether you are debugging an API that changed its response shape, reviewing config drift between environments, or verifying test fixtures after a refactor, a structured diff saves time and catches issues that manual scanning misses.
Key differences vs value differences
A key difference means a field exists in one document but not the other — it was added or removed. A value difference means both documents have the same field, but the data at that path changed. Separating these two categories helps you decide whether a change is structural (a new column in the schema) or just a data update (a price went from 100 to 120).
The NxtTls JSON Diff tool lets you filter by Keys, Values, or Both so you can focus on exactly the kind of change you care about.
Navigating nested JSON with collapse and expand
Real-world JSON is deeply nested — objects inside arrays inside objects. A flat list of every changed path would be overwhelming. The diff viewer uses a collapsible tree: expand a node to drill into its children, or collapse it to hide noise. Use Expand All and Collapse All to switch between a high-level overview and full detail.
Common use cases
API version migration: paste the old and new responses to see exactly which fields were added, renamed, or dropped. Environment config auditing: compare staging and production JSON configs to catch unintended overrides. Test fixture validation: after a data migration script, diff the before and after fixtures to confirm only expected rows changed.
Try it on NxtTls
Paste your original JSON on the left, the modified version on the right, and hit Compare. Filter by keys or values, expand or collapse nodes, and copy the results. Everything runs in your browser — no data leaves your machine.
Try the tool
JSON Diff