Font Loading API Demo - Online Wait for Fonts Ready
Use the document.fonts API to check if a font is loaded. Watch the ready promise. Avoid FOUT. JavaScript demo.
UD5 Toolkit
Securely browse and preview all fonts installed on your computer using the Font Access API.
Works on Chrome 103+ | Your fonts stay local
Accessing your local fonts...
You may be prompted to grant permissionUnable to access local fonts
Permission denied or an error occurred.No fonts match your search
Try adjusting your search terms or clearing the filterUse the document.fonts API to check if a font is loaded. Watch the ready promise. Avoid FOUT. JavaScript demo.
Select a local font and see all its metrics: ascent, descent, x‑height, and supported features. Typography deep dive.
Paste a Base64 encoded font string and generate the complete @font‑face CSS rule. Inline small fonts easily.
Paste two strings that look the same and see if they differ after normalization. Debug invisible encoding bugs.
Enter a city name or coordinates and see today's sunrise, sunset, and twilight times. Approximate algorithm. Local.
Load a WAV file and see its real-time oscilloscope trace and frequency spectrum. Zoom and pan. Pure frontend.
Search by country or currency name to find its symbol and code. Quick static reference for international business.
For any latitude and date, calculate the exact daylight hours. See golden hour. Useful for gardening and travel.
Calculate antenna element lengths for a given frequency (or vice versa). Supports 1/4 wave, 1/2 wave, dipole. Useful for ham radio. Local only.
Enter target total weight and bar weight to see which plates to put on each side. No more counting errors.
Automatically remove the background from any photo using a small on‑device AI model (WASM). No upload. Works offline.
Compress and decompress text using the browser's native Compression Streams API. See the binary output size.
Connect a game controller and see every button press, axis movement, and vibration test. Uses the Gamepad API.
Unified input demo: see pressure, tilt, and type from any pointer. Compare pointerType values. Essential for drawing apps.
Decode an image progressively using the ImageDecoder API. See partial results and metadata. Modern alternative to <img>.
Decode individual video frames from a local file using the VideoDecoder API. Step through frames. Cutting‑edge browser feature.
Write to shared storage and run a worklet to process data. Learn the privacy‑preserving alternative to third‑party cookies.
Experiment with the Federated Credential Management API. Simulate a sign‑in flow without third‑party cookies. Privacy‑first.
Register a one‑off background sync and see it fire when connectivity returns. Debug service worker sync logic.
Request HID devices and list them. Read input reports and send output. For custom hardware and controllers.
Read the ambient atmospheric pressure in hPa using the Pressure Sensor API (if available). Real‑time graph.
Request permission and detect when the user is idle (away from keyboard). See screen lock state. For native‑like apps.
Demonstrate how the Web OTP API automatically reads one‑time codes from SMS (mobile). Simulation with a fake SMS input.
Acquire and release locks across tabs. Prevent race conditions in IndexedDB or localStorage. Visual queue and lock state.
Connect a gamepad and see all button presses and axis movements visually. Check that every input is detected correctly.
Trigger different vibration patterns on mobile devices. Test if your phone supports haptic feedback. Simple demo.
Check notification permission, request it, and send a test notification. Verify icon, body, and tag. Debug web push.
Display your effective connection type (4g, 3g, etc.) and downlink speed using the Navigator API. Adapt your app accordingly.
See your device's battery level, charging status, and discharge time using the Battery Status API. Fun utility.
Check current screen orientation and test the lock API. Useful for mobile web apps. Demo with code.