JSON Diff
Compare Two JSON Objects Online
Free online JSON diff tool to compare two objects, find differences between API responses, and detect structural changes instantly. This browser-based JSON comparator understands document structure, so it catches value changes, type mismatches, and missing properties that a plain text diff would miss or misreport.
Built for payloads you wouldn't paste into a random website. Parsing, normalization, and the diff itself all happen inside the browser tab — no upload endpoint, no background sync, no logging. Use it on API responses with tokens, config files with secrets, or any data you'd rather keep off a third-party server.
Semantic JSON Comparison, Not Text Diff
Text diff tools get confused by reformatted JSON: a pretty-printed file looks completely different from a minified one even when the data is identical. This tool parses both inputs, sorts keys, and compares by structure. Whitespace, key order, and formatting differences are ignored; only real data changes are reported.
Three Types of JSON Differences
Every change between two JSON documents falls into one of three categories. Each difference is labeled so you can see at a glance what kind of change you're looking at.
Value Differences
Same key, same type, different value. The most common kind of change - a name updated, a number adjusted, a boolean flipped.
"name": "John" -> "Jane" "age": 30 -> 25
Type Mismatches
Same key, but the value changed type. Often caused by a stringified number slipping into an API response, or a boolean becoming a string during serialization.
"age": 30 -> "30" "active": true -> "true"
Missing Properties
A key exists on one side but not the other. Useful for catching fields that were added, removed, or accidentally dropped between API versions.
Left: { "email": "..." }
Right: { } // missingHow To Compare Two JSON Files Online
Four steps, no sign-up. This is all it takes to diff JSON online and see exactly what changed between your documents.
Paste Left JSON
Drop your first document into the left editor. Invalid syntax shows a parse error with a line and column pointer so you can fix it before comparing.
Paste Right JSON
Paste the second document into the right editor. Both inputs are parsed client-side and normalized before the diff runs.
Review Differences
Differences are categorized as value changes, type mismatches, or missing properties, each colour-coded and tagged with the full key path.
Jump And Fix
Click any difference to jump to that exact position in both editors. Edit in place to resolve a diff without leaving the page.
Why Use This JSON Compare Tool
A JSON diff checker that reads your data structurally, runs entirely in the browser, and surfaces the information you actually need.
Structural JSON Diff
Keys are sorted and compared by path, not position. Reformatting a file won't produce false differences - only real data changes are reported.
Type-Aware Comparison
The comparator distinguishes between 30 (number) and "30" (string) and flags it as a type mismatch, not a simple value change.
100% Private And Secure
Your JSON never leaves the browser tab. Unlike tools that upload to a server, this one runs entirely client-side - safe for API keys, PII, and internal schemas.
Deep Nested Comparison
Recursively compares nested objects and arrays at any depth. Each difference reports the full path, like user.addresses[0].city.
Instant Results
Differences update on every keystroke. No Compare button, no processing delay - the diff runs incrementally as you edit.
No Sign-Up Required
Start comparing immediately. No registration, no email, no quotas. Free for personal and commercial use, with no premium tier gating features.
What You Can Compare
If it's valid JSON, this tool can compare it. These are the situations where a structural JSON diff pays off the most.
API Development
Compare API responses between environments, versions, or branches. Spot breaking changes before they ship, and confirm that a migration produced the expected payload.
- Response diffs across staging and prod
- Breaking change detection between API versions
- Snapshot comparison for contract tests
- Webhook payload investigation
- GraphQL response shape audits
Configuration Files
JSON configs are everywhere - package.json, tsconfig.json, eslintrc, CloudFormation, IAM policies. Diff them to find exactly which setting changed between branches or deploys.
- package.json dependency diffs
- tsconfig.json strictness changes
- .eslintrc and prettier config drift
- AWS IAM policy comparisons
- CloudFormation template reviews
Data & Analytics
Compare JSON exports, analytics payloads, and NoSQL documents. Useful for data migrations, feature-flag audits, and tracking document-level changes over time.
- MongoDB and Firestore document diffs
- Analytics event schema drift
- Feature-flag payload comparisons
- JSON Schema validation diffs
- ETL input vs output verification
Compare JSON In JavaScript
Developers often need to compare two JSON objects in JavaScript. A simple JSON.stringify comparison works for shallow equality, but misses reformatting, key ordering, and type coercion.
// Simple JSON comparison const json1 = { name: "John", age: 30 }; const json2 = { name: "Jane", age: 30 }; // Simple equality check (won't work for objects) JSON.stringify(json1) === JSON.stringify(json2); // false // For deep comparison, you need recursion // or use our tool for instant visual diff!
This online JSON diff tool does the semantic comparison for you - type checking, path tracking, and missing-property detection included. Much more useful than string equality when you're debugging an API or reviewing a config change.
Frequently Asked Questions
What is a JSON diff tool?
A JSON diff tool, also called a comparator or difference checker, compares two documents and reports what changed. Unlike a text diff it understands structure, so it can distinguish value changes from type changes and identify missing properties regardless of key order or formatting.
How do I compare two JSON files online?
Paste the first document in the left editor and the second in the right editor. The tool parses both sides, sorts keys, and shows every difference categorized by type. Click any diff to jump to its location in both documents.
Is this online JSON diff tool free?
Yes. It's 100% free for personal and commercial use. No sign-up, no usage quotas, no paid tiers, and no watermark on any export.
Is my JSON data secure?
Yes. Parsing, key sorting, and the diff itself execute in your browser's JavaScript engine; there is no backend endpoint that receives the data. This is the right choice when the payload contains bearer tokens, internal user IDs, or any field your security team wouldn't want on a third-party log. The Share link is hash-fragment-based, so even shared URLs don't transmit the data to the server.
What is semantic JSON comparison?
Semantic comparison treats input as data, not text. It parses both sides, normalizes formatting, sorts keys, and compares values by path. This means reordered keys, different indentation, and minified vs pretty-printed files don't create false differences.
Does this tool compare nested JSON?
Yes. Nested objects and arrays are compared recursively at any depth. Each difference is reported with its full path, like orders[0].items[2].price, so you can locate the change exactly in your source data.
What happens if my JSON is invalid?
The editor highlights syntax errors with a line and column pointer and a short description of the problem. Common causes are missing quotes, trailing commas, unescaped characters, or single quotes where double quotes are required. Fix the error, and the diff runs automatically.
Can I compare JSON with different key order?
Yes, and this is the main advantage over a plain text diff. Keys are sorted alphabetically before comparison, so two documents with the same data in different key order are reported as identical.
Does this JSON compare tool handle arrays?
Yes. Arrays are compared element by element, with each position tracked as part of the path. Added, removed, and modified elements are reported individually, so you can see exactly which index changed.
Can I use this offline?
Yes. Once the page has loaded, the tool runs entirely in the browser. You can disconnect from the network and keep comparing without any loss of functionality.
Start Comparing JSON Online - Free
Scroll up and paste your JSON. No sign-up, no downloads, no limits.