Compare two API responses side by side with structural diff, value changes, and schema drift detection.
This tool takes two JSON API responses, one as the baseline and one as the comparison, and walks both trees key by key to report what changed. It separates structural drift (fields added, removed, or changed type) from ordinary value changes, so a renamed or missing field reads differently from a value that simply got updated. The part people miss most: object key order never counts as a difference, but array element order does, so two arrays holding the same items in a different sequence often show up as changed even though nothing meaningful moved.
A concrete input and expected output from the current implementation.
Input
A: {"id": 1, "name": "Alice", "role": "admin"}
B: {"id": 1, "name": "Alice", "role": "editor", "active": true} Expected output
id: unchanged (1)
name: unchanged ("Alice")
role: changed, "admin" -> "editor"
active: added in B, value true (boolean), absent from A id and name match exactly in both payloads, role has the same key in both but a different value, and active exists only in B, so it is reported as an added field rather than a value change.
The tool parses both pasted responses as JSON, then recursively walks the two trees together, matching nodes by key path. At each path it classifies the result as unchanged, added, removed, or changed, and reports scalar value changes, such as a string or number that differs, separately from structural changes like a field disappearing entirely.
Independent of whether values match, the tool compares the key set and JSON type (string, number, boolean, object, array, null) of each field across both payloads. A field present in only one response, or one whose type changed between responses, such as an id switching from number to string, is flagged as drift even when a human might read the values as equivalent.
No. Both responses are parsed as JSON objects before comparison, and JSON itself defines objects as unordered key-value sets, so two objects with identical keys and values in a different order are treated as equal with no diff reported for the reordering.
No, it expects valid JSON on both sides. Pasting XML, HTML, or plain text will either fail to parse or get treated as one unparsed value rather than being broken into comparable fields. For XML responses, use a dedicated XML comparison tool instead.
The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.
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