UD5 Toolkit
Audio/Video Sync Tester - Online Lip Sync Check
Load a video and visually check if audio aligns with lips. Use frame‑by‑frame stepping. Debug playback issues.
Tag: Network Connectivity Test
65+ toolsEye Dominance Test - Online Find Your Dominant Eye
Simple interactive eye dominance test: hold up a virtual dot and see which eye stays aligned. Educational.
Browser Color Gamut Test - Online P3 or sRGB?
Check if your browser and display support the wider DCI‑P3 color space. See the difference with a simple test pattern.
Test Credit Card Validator - Online Luhn Check & Issuer
Paste a test card number to verify Luhn algorithm, identify issuer (Visa, MC), and check length. No real data.
Microphone Sensitivity Tester - Online Input Level Meter
See a live VU meter of your microphone's input level. Test if your mic is working and adjust gain. Privacy‑friendly.
HTTP Request Composer - Online Build & Send Requests
Pick a method, URL, headers, and body, then send an HTTP request directly from your browser. Debug APIs easily.
Fake ID Number Generator - Online Test SSN/SIN Lookalike
Generate random, formatted ID numbers that match pattern rules for various countries. For testing input validation. No real data.
Speaker Test Tones - Online Left/Right Channel & Sweep
Play left‑only, right‑only, and frequency sweeps to test your speakers or headphones. Quick audio check.
Fullscreen API Tester - Online Request & Exit Demo
Test the Fullscreen API: request fullscreen on a colored div, detect changes, and copy the JavaScript boilerplate.
Random MAC Address Generator - Online Hardware Test IDs
Generate valid, random unicast MAC addresses for testing or spoofing. Select OUI prefix if desired. Local only.
Geolocation API Simulator - Online Test Coordinates
Override your browser's geolocation to any coordinates and test how your app responds. For development and privacy testing.
Media Device Tester - Online Check Camera, Mic & Speaker
Quickly test if your webcam, microphone, and speakers work correctly. See live video and audio meter. No data sent.
Iframe Sandbox Configurator - Online Test Permissions
Build an iframe with different sandbox flags and see live which features are blocked. For secure embedding.
Fuzzy Data Generator - Online Create Random Records
Generate random but realistic‑looking data arrays (users, products, orders) with typos and missing fields. For test robustness.
Random User Activity Simulator - Online Test Idle Logic
Simulate random mouse moves, clicks, or keystrokes to test idle‑timeout logic. Stops when you move the mouse. Dev test.
Palindrome Tester - Online Phrase Checker
Enter any phrase and instantly see if it's a palindrome, ignoring spaces and punctuation. Fun for word nerds.
Clinical Color Blindness Tester - Online Ishihara Plate Style
View a series of digital Ishihara‑style plates. Not a diagnostic tool, just educational. Read numbers.
Periodic Background Sync Tester - Online Register & Test
Register a periodic background sync and see the status. Schedule content updates for your PWA. API demo.
Accept‑Language Header Visualizer - Online Locale Match
Paste your Accept‑Language header and see which languages your site should serve based on quality values. Internationalization helper.
Push Notification Tester - Online Generate & Receive
Register a service worker, subscribe to push, and send a test notification using a VAPID key pair. Step‑by‑step demo.
Web Share API Tester - Online Demo & Code
Test the Web Share API by sharing text, links, and files directly from the browser. Check compatibility and see example code.
Geolocation Override Tester - Online Simulate Any Location
Override your browser's geolocation to any coordinates and test how your app responds. For development and privacy testing.
PWA Install Prompt Tester - Online Simulate Install
Check if your page triggers the beforeinstallprompt event. Simulate the install flow. Debug PWA installability.
X‑Frame‑Options Tester - Online Clickjacking Defense
Check if a URL can be embedded in an iframe. Test your site’s defense against clickjacking. Browser‑based.
Screen Orientation API Tester - Online Lock & Check
Check current screen orientation and test the lock API. Useful for mobile web apps. Demo with code.
Playwright Test Skeleton - Online Script Boilerplate
Create a basic Playwright script with browser launch, page navigation, and screenshot. Start E2E testing instantly.
Web Notification Tester - Online Permission & Display
Check notification permission, request it, and send a test notification. Verify icon, body, and tag. Debug web push.
SSE (EventSource) Tester - Online Stream Listener
Connect to an SSE endpoint and display events in real time. Inspect event types and data. Handy for frontend devs.
Multi‑Device Tester - Online See Website on 3 Sizes
Enter a URL and view it in three iframes: mobile, tablet, and desktop side‑by‑side. Quick responsive check.
Screen Wake Lock Tester - Online Keep Screen On
Toggle a screen wake lock to prevent the device from dimming or sleeping. See the lock state and learn the API.
Network Throttle Simulator - Online Slow 3G & Offline Test
Test how your page loads under slow, 3G, or offline conditions by intercepting fetch and applying delays. No DevTools needed.
Astigmatism Self‑Check Chart – Online Dial & Lines
Display an astigmatism dial and instructions for self-assessment. Educational, not a medical diagnosis.
Finger Reaction Time Test – Online Tap When Color Changes
Wait for the box to turn green, then tap as fast as possible. Measure milliseconds. Compete with friends.
Unicode Normalization Tester - Online See NFC vs NFD
Paste two strings that look the same and see if they differ after normalization. Debug invisible encoding bugs.
CORS Proxy Emulator - Online Test Cross‑Origin Requests
Bypass CORS for testing by routing requests through a local service worker proxy. Debug APIs without server changes. Experimental.
WebTransport Echo Client - Online QUIC Test
Connect to a WebTransport server and exchange data over QUIC. See latency and throughput. Perfect for exploring low‑latency real‑time APIs.
forced‑colors Mode Tester - Online Windows High Contrast
Simulate forced‑colors mode and see how your site looks. Adjust CSS system colors. Make your design accessible.
WebSocket Test Client - Online Connect & Send Messages
Connect to a WebSocket endpoint, send messages, and view the stream of received data. Perfect for debugging real‑time apps.
Jest/Vitest Unit Test Generator - Online Function Stub
Write a function name and get a complete unit test stub with describe, it, and expect. Follows AAA pattern.
Random English Name Generator - Online First & Last
Generate a random first and last name typical for US, UK, or Australia. With optional middle initial. Useful for test data.
Web Share Target Tester - Online Receive Shared Content
Simulate a PWA receiving shared text, links, and images. Test the Web Share Target API without a server.
Content Indexing API Test - Online Add to Device's Media Feed
Test the Content Indexing API to add a page to the device's content feed. See how your PWA integrates with the OS.
Offline Capability Checker - Online Test PWA Readiness
Check if your site has a service worker registered and if it can load offline. Quick PWA readiness assessment.
Candle Wick Testing Log – Online Record & Compare Burn Results
Log pool depth, flame height, and soot for each wick series. Quickly identify the best wick for your wax and vessel.
Speaker Polarity Test – Online Click & Listen
Generate a pop signal to determine if speakers are wired in phase. Quick stereo test.
Snellen Eye Chart – Online Visual Acuity Test Simulation
Display a Snellen chart on screen and mark distance for a fun self-test. Not a replacement for professional exam.
React Testing Library Skeleton - Online Test Boilerplate
Enter a component name and generate a complete RTL test file with render, screen, and common assertions. Fast testing setup.
Connection Speed Estimator - Online Download Test
Quickly estimate your internet connection speed by downloading a small test file. See class and recommendations.
Notification Permission Checker - Online Manage & Test
See your current notification permission status. Request or reset it. Test browser notification behavior.
API Request Builder - Online Test REST Endpoints
Select HTTP method, set headers, and body. Send requests and see the full response. Lightweight Postman alternative.
Reaction Time Test - Online Click & Sound
Measure your visual and auditory reaction speed. Average and best times shown. No data collected. Pure Javascript timing.
prefers‑reduced‑motion Tester - Online A11y Check
Simulate reduced motion preference and test your animations. Copy the media query snippet. Keep your users safe.
3D Printer Bed Leveling Test Generator – Online STL Preview
Create a simple 3D bed-leveling test pattern (circles/squares) as a vector, preview, download SVG for extrusion.
Pseudo‑Localization Generator - Online Test UI for i18n
Transform English text into pseudolocalized text with accents, expansion, and brackets. Test your UI's readiness for translation.
Online Ping Test - Measure Latency to Servers
Send HEAD requests to popular websites and measure the round‑trip time. Quick network health check. Client‑side.
Color Personality Test – Online Fun What Hue Are You?
Answer a few questions and get a playful color-based personality result. For entertainment only.
Speech Utterance Tester - Online Play Word by Word
Hear text spoken word by word with boundary events. See the exact index and character. Advanced TTS dev tool.
Brotli Compression Level Tester - Online Optimal Setting
Compress text with Brotli at different quality levels. See size reduction and time. Find the sweet spot for your static assets.
Subwoofer Phase Tester – Online Audio Check
Play low-frequency tones to check subwoofer phase alignment with main speakers. Simple tool.
Visual Stress Pattern Checker – Online See Effect
Display striped patterns that can cause visual distortion. Learn about visual stress. Switch colors.