ToolzyLab
Compare two JSON objects or files side by side, validate them instantly, and highlight added, removed, changed, and type-changed values visually. Perfect for API responses, config files, payloads, exported data, and structured debugging.
Paste JSON into both panels or upload two files. This tool validates, beautifies, normalizes, compares deeply, and gives you a clean visual diff with paths, old values, new values, and summary counters — all locally in your browser.
Drop or select the original / old / source JSON file.
📄 left JSON · original dataDrop or select the updated / new / target JSON file.
📄 right JSON · updated dataPaste raw JSON in both editors. The tool validates, beautifies, and compares them deeply.
Each row shows the JSON path, change type, and before/after value snapshot.
Inspect every changed path with old and new values side by side.
Quick human-readable report of validation and diff results.
No report yet.
Helpful tips for tricky comparisons.
A JSON diff should compare data structure rather than indentation. Load two valid documents, choose array behavior, numeric-string and trim options, path filtering, preview depth, unchanged-node visibility, and primary view, then inspect added, removed, changed, and type-mismatched values at their exact paths.
Comments, trailing commas, single quotes, NaN, undefined, and duplicate-key behavior are common sources of confusion. Validate and beautify both sides first. Parsers typically keep only one value for a duplicate object key, so fix ambiguous input before relying on a diff report.
A reordered list can be either a real change or an equivalent set depending on the contract. Numeric strings and numbers can look similar but behave differently in schemas and APIs. Enable coercion only for a known comparison goal, and review duplicates when treating arrays without order.
Filter to a subtree when investigating one contract, then return to the full document before approval. Expanded previews help understand nested objects, while a concise report helps sharing. Protect secrets in payloads and reports, and use schema validation when field presence and type rules matter.
Record the comparison options because they affect what counts as a difference.
Technical references: RFC 8259 JSON specification
A structural comparison parses values, so ordinary whitespace and indentation outside strings do not matter. Whitespace inside string values can still be significant.
Only when the application treats the array as an unordered set. Lists, priority rules, coordinates, and event sequences usually depend on order.
Not in JSON. They have different types. Coercing numeric strings can reduce noise for a specific dataset but may hide a contract-breaking change.
JSON interoperability expects unique names, but parser behavior often keeps one value. Resolve duplicate keys before comparison because earlier data may already be lost.
It narrows the report to a selected property or subtree. Use it for investigation, then review the full document before approving a change.
No. A diff compares two instances; a schema checks required properties, allowed types, formats, ranges, and other contract rules.