JSON Diff — Compare Two JSON Files

Text diff (like git diff) compares line-by-line and flags formatting changes such as whitespace, indentation, and property reordering. JSON diff parses both documents into structured data and compares semantically — it only surfaces actual data changes like added/removed properties, changed values, and type modifications. Property order changes are correctly ignored since they do not affect JSON meaning per the spec.

The tool supports three array comparison strategies: (1) Index-based (default) — compares items at the same position, best for ordered arrays; (2) Content-based — ignores order and matches items by their content, useful for unordered sets; (3) Key-based — for arrays of objects, matches items by a specified key field (like "id") so reordered items are diffed correctly instead of showing as add+remove pairs.

Yes. Type changes are flagged as high-severity differences because they commonly cause runtime errors: number to string, null to value, primitive to object, array to non-array, etc. These are highlighted prominently in the diff output and listed separately so they are never overlooked.

Yes. The diff engine compares JSON files up to 5 MB near-instantly and handles files up to 20 MB within a few seconds. All processing happens in your browser using an optimized recursive diff algorithm. For files larger than 50 MB, consider using command-line tools like jd or json-diff.

The JSON specification states that object key order is not significant. Our diff tool correctly ignores property order changes — if two objects have the same keys and values but in a different order, they are reported as equal. This prevents noise in your diff results and matches how JSON is actually processed by parsers.

Many teams use JSON diff as part of their CI/CD pipeline to compare expected vs actual API responses. You can save baseline JSON fixtures in your repo, fetch the current API response in CI, and fail the build if breaking changes (removed fields, type changes) are detected. This tool is ideal for manual verification; for automated use, pair it with libraries like deep-diff or jest-json-schema.

Yes. Every difference includes its full JSONPath expression (e.g., $.data.users[2].address.zipCode). This makes it trivial to locate the changed property in your code, update your TypeScript interfaces, or fix your test fixtures. You can click any path to copy it.

JSON with comments (JSONC) or trailing commas is technically not valid JSON per RFC 8259. The diff tool uses a lenient parser that handles these common deviations, so pasting JSON from VS Code settings.json or tsconfig.json works correctly even if they contain comments.

A property with a null value and a missing property are treated as different states. If the left document has {"name": null} and the right has no "name" key at all, this is reported as a removal. This distinction matters because many APIs and databases treat null and missing differently.