ArrayDiff is a free developer tool for comparing arrays and JSON data side by side. It highlights what was added, removed, or changed — with color-coded visual diffs. It works with data from any language (Python, JavaScript, PHP, Ruby, Go, Java) and runs entirely in your browser for complete privacy.
Common Use Cases:
API TestingConfig ValidationData MigrationTest AssertionsCode ReviewCopy and paste your arrays (from any programming language) into the two input panels. Supports arrays with strings, numbers, objects, and nested arrays from Python, JavaScript, PHP, Ruby, Go, and more.
Click "Compare Arrays" to see the differences highlighted in real-time. Added elements are green, removed are red, and modified are yellow.
Review the detailed comparison results with element counts and visual indicators for each type of change.
Practical examples where array comparison saves developers time and prevents bugs across all programming languages.
Compare REST API responses before and after version updates to ensure backward compatibility.
Before: [{"id": 1, "name": "John"}] → After: [{"id": 1, "name": "John", "email": "john@example.com"}]Validate configuration arrays across different environments to prevent deployment issues.
Staging: [{"feature": "auth", "enabled": true}] vs Prod: [{"feature": "auth", "enabled": false}]Compare expected vs actual test results to identify failures and data inconsistencies.
Expected: [{"status": "success", "count": 5}] vs Actual: [{"status": "success", "count": 3}]Compare database query results before and after migration to ensure data integrity.
Old: [{"user_id": 1, "role": "admin"}] → New: [{"userId": 1, "permissions": ["read", "write"]}]Everything runs in your browser. Your data never leaves your device — no server uploads, no tracking of input content.
Color-coded results: green for added, red for removed, yellow for modified. Spot changes at a glance.
Recursively compares nested objects, arrays within arrays, and complex JSON structures at any depth.
Keyboard shortcuts (Ctrl+Enter to compare, Ctrl+L for sample data), syntax highlighting, and mobile support.
Pure JavaScript with no external libraries. Loads instantly, works offline once loaded, and handles large datasets efficiently.
Accepts JSON arrays, Python lists, JavaScript arrays, and any structured data that can be represented as JSON.
Free browser-based tools for everyday dev tasks. All private, all instant.
Diff & Compare
Compare two JSON objects or documents. See added, removed, and changed keys with path-based highlighting.
Compare plain text or code line by line with word-level highlighting. Side-by-side view.
Compare CSV or TSV files with a table-based view. Custom delimiters and key column matching.
Encode / Decode / Format
Format, beautify, minify, and validate JSON with customizable indentation and key sorting.
Encode text to Base64 or decode Base64 back to text. Full UTF-8 support.
Encode URLs with encodeURI or encodeURIComponent. Decode percent-encoded strings.
Decode JSON Web Tokens to view header, payload, and signature with expiry status.
Any JSON-formatted data: arrays of strings, numbers, booleans, objects, nested arrays, and null values. If your language can output JSON, ArrayDiff can compare it.
Yes. All processing happens in your browser — no data is sent to any server. The tool even works offline once loaded.
Arrays with thousands of elements work smoothly. Performance depends on your device, but the tool is optimized for large datasets.
Yes — ArrayDiff performs deep comparison at any nesting level, including objects within arrays, arrays within arrays, and mixed structures.
Any language that outputs JSON-compatible data: Python lists, JavaScript arrays, PHP arrays, Ruby arrays, Go slices, Java, C#, and more.