An API response diff compares two HTTP responses — status codes, headers, and body — so you can quickly find discrepancies between environments, API versions, or test runs. Paste the responses from staging and production to see every structural difference highlighted.
Response A (Original)
Response B (Modified)
Status Code Comparison
Headers Diff
Body Diff
How to Compare API Responses
When two API calls return different results, pinpointing the exact difference saves hours of debugging. This API response diff tool breaks the comparison into three sections — status codes, headers, and body — so you can quickly isolate the cause of a discrepancy.
Step 1: Enter Both Responses
For each response, fill in the status code (e.g. 200, 404, 500), paste the headers in Name: Value format (one per line), and paste the body. For JSON responses, paste the raw JSON string. For XML or REST APIs returning XML, paste the XML body directly — the tool will detect the format automatically.
Step 2: Click Compare Responses
The tool performs three simultaneous comparisons. Status codes are checked for equality and shown as Match or Mismatch. Headers are diffed by name, with added/removed/changed headers color coded. The body is parsed and deep-compared — for JSON it shows the exact field path that changed, for XML it compares element structure, and for plain text it falls back to line-by-line diff.
Common API Debugging Workflows
Use this tool to compare staging vs. production API responses to catch environment-specific data issues. Compare a successful request against a failed one to see which response fields differ. Validate that a new API version returns the same data structure as the old version. Check that headers like Cache-Control, Content-Type, and CORS headers are consistent between environments.
FAQ
Is the API response diff tool free?
Yes, fully free with no signup required. All comparison logic runs in your browser — your API responses are never sent to any server, making it safe for internal API payloads.
What formats does the body comparison support?
The tool auto-detects JSON and XML in the body fields. For JSON bodies, it performs a deep structural diff showing added, removed, and changed fields by path. For XML, it uses DOMParser to compare element structure. Other text bodies fall back to line-by-line text diff.
How do I compare HTTP headers?
Paste headers in the standard HTTP format: one header per line as Name: Value. For example, Content-Type: application/json on its own line. The tool parses all headers and shows which were added, removed, or changed in value.
What do the status code indicators mean?
If both responses have the same status code, it shows a green Match badge. If they differ, the tool highlights both codes in red to draw immediate attention to the mismatch — useful when debugging why two environments return different status codes for the same request.
Can I use this to compare staging vs. production APIs?
Yes, this is the primary use case. Make the same request against your staging and production environments, paste the full responses (status, headers, body), and the tool instantly shows every difference — including subtle JSON field changes that could indicate data inconsistencies.
Does this work for GraphQL API responses?
Yes. GraphQL responses are JSON, so paste the JSON body from your GraphQL endpoint into the body field and the deep JSON diff will compare the data and errors fields. The status code comparison also works since GraphQL responses use standard HTTP status codes.