Reaction Time Test - Online Click & Sound
Measure your visual and auditory reaction speed. Average and best times shown. No data collected. Pure Javascript timing.
UD5 Toolkit
Online LeetCode Practice Clock – simulate real interview time pressure, track performance per question, and boost your confidence.
Measure your visual and auditory reaction speed. Average and best times shown. No data collected. Pure Javascript timing.
Toggle a screen wake lock to prevent the device from dimming or sleeping. See the lock state and learn the API.
Request and release a screen wake lock to keep the device awake. See the lock state in real time. Perfect for recipes or presentations.
Evaluate password strength through a short interactive story where each character set adds lines to a narrative. Educational fun.
Tap any key to measure beats per minute. Displays average BPM and beat interval in milliseconds. Essential for DJs and music production. No extra permissions.
Press any key and see it light up on a standard QWERTY layout. Check functionality or demonstrate shortcuts.
Tap any key to the beat of a song and the tool calculates the BPM. Also shows average and millisecond delay for loops.
Generate a bcrypt hash from a password with configurable salt rounds. Verify a password against a hash. Entirely client‑side.
Create secure passwords that look like gibberish words but are easy to pronounce and remember. Mix of syllables. Local generation.
Play pure tones at various frequencies to estimate your hearing range. Simple and educational.
A sound-enabled spinning wheel with your custom options. Exciting animation and result reveal. Local only.
Simple interactive eye dominance test: hold up a virtual dot and see which eye stays aligned. Educational.
Create a random long password that alternates consonants and vowels to mimic a pronounceable word. XKCD meets CVCV. Local.
Touch your screen and see the pressure and radius reported. Visualize force. Mobile developer tool.
Write upside down text using Unicode flipped characters. Copy and paste to surprise friends. Completely frontend and instant.
Enter a word and get a list of perfect and near rhymes. Categorized by syllable count. Useful for songwriting and poems. Static data, local.
Compare your password against a built‑in list of the 10,000 most common passwords. Instant warning if it appears.
Select your bin type and get a custom instruction on securing it with bungees, straps, or locks.
Schedule your iron supplement away from inhibitors (coffee, calcium). Visual reminder and log.
Set a short timer with a themed emoji animation (e.g., pizza cooking). A playful visual countdown.
Animated circle guides your breathing: breathe in, hold, breathe out. Customizable ratios (e.g., 4-7-8). Soothing colors, optional bell sound. Purely local.
Select tea type and get recommended steeping time & temperature. Start a visual countdown with an alert. Make every cup perfect. No ads, local.
Practice calculating network ID, broadcast address, and usable IPs from a random IP/CIDR combination. Instant feedback and score tracking. Perfect for CCNA prep.
Guided breathing exercises with animated circle for inhale/hold/exhale. Includes box breathing, 4-7-8, and resonant breathing patterns. Customizable intervals.
Randomly generated subnetting questions. Calculate network address, broadcast, and usable range. For CCNA prep.
Set a meditation duration with optional interval chimes. Soothing bell sounds at the start and end. No ads.
Use your keyboard or mouse as a straight key. Hear the tone and see the dots/dashes. Perfect for learning CW. Local.
Pomodoro timer that saves completed sessions to localStorage. View daily/weekly stats. Boost productivity with data.
Generate a random HTML/CSS card with different box model properties. Inspect and guess the size. For learners.
Run up to 4 independent stopwatches at once with labels. Perfect for timing multiple tasks or sprints.