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.
UD5 Toolkit
Test your browser's privacy‑preserving anti‑fraud capabilities
Click the button to detect if your browser supports Private State Tokens (formerly Trust Tokens).
Simulate a real‑world issue & redeem flow. This demonstrates how websites can distinguish humans from bots without tracking you.
How to request a token from an issuer in JavaScript:
type: 'token-redemption' in a fetch request to your site. See
Chrome developer docs.
chrome://flags/#private-state-tokens. No browser extension is required.
fetch API with privateToken options, as shown in the code example above.
Write a function name and get a complete unit test stub with describe, it, and expect. Follows AAA pattern.
Check if your site is cross‑origin isolated by examining the COOP and COEP headers. See if SharedArrayBuffer is available.
Intercept and manage navigations without reloading. Test transition handling and URL updates. The future of client‑side routing.
Generate short, URL‑safe, unique string IDs with customizable alphabet and length. Smaller than UUID. Local only.
Generate UUID v7 identifiers that are lexicographically sortable and timestamped. Perfect for databases. All local.
Generate a valid BookCrossing BCID with checksum for your free book tracking label. Follows BCID format rules. Fun for sharing books.
Spin the globe and get a random country or city to visit. Learn a fun fact. Plan your next adventure. Local data.
Create Latin squares for experimental design or tournament scheduling. Visual and copyable. No server required.
Encode letters to their position in the alphabet (A=1, B=2...) and decode back. A classic puzzle tool. No data leaves your device.
Write CSS with native nesting (like SCSS) and see the browser’s native parsing. Validator and live output.
Encode text into Wingdings symbols and decode Wingdings back to text. A nostalgic and fun puzzle tool. All processing in your browser.
Convert climbing difficulty between V‑scale, Fontainebleau, and Yosemite Decimal System. Quick reference for gym climbers.
Experiment with CSS Grid properties visually. Add rows, columns, and areas. See the grid in action and copy the code.
Upload a photo, enter details, and create a tear-off style lost pet poster. Instant PDF download.
Drag items into grid cells and see the resulting grid‑area or line‑based placement code. Learn how auto‑placement and spanning work.
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.
Toggle a screen wake lock to prevent the device from dimming or sleeping. See the lock state and learn the API.
Test the experimental Translation API to translate text between languages directly in the browser, without cloud calls. Check support and copy the JavaScript starter.
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 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.
Schedule tasks with user‑visible, user‑blocking, or background priority. See execution order and delays. Modern web perf.
Connect a gamepad and see all button presses and axis movements visually. Check that every input is detected correctly.