Barcode Scanner Simulator – Online Enter Number & Visualize
Type a UPC or EAN number and see how a laser scanner would identify it, plus check digit validation.
UD5 Toolkit
Type a UPC or EAN number and see how a laser scanner would identify it, plus check digit validation.
Drag a battery, resistor, LED onto a grid and simulate current flow. Show Ohm's law in action.
Type JavaScript expressions and see output like a real browser console. Supports console.log, error, warn. Use for quick testing without DevTools.
Change the viewport meta tag and see how a page would render at different device widths. Understand responsive basics.
Upload a gradient or enter a palette and simulate how it appears with different types of color vision deficiency. Ensure inclusive data visualization.
Virtually fold a digital paper and cut out shapes to see a snowflake unfold. Experiment with designs before real scissors. Pure creative fun.
Write a simple assembly program and see the pass‑1 and pass‑2 symbol tables and object code. Systems programming helper.
Enter processes and see how different scheduling algorithms handle them. Gantt chart generation. OS course helper.
Upload an image and see a rough simulation of how it might look when printed. Highlights areas that may lose detail.
Simulate adaptive bitrate logic by switching between different quality video segments. See how ABR algorithms work.
Input telescope and eyepiece parameters to see a simulated view of the Moon or Andromeda. Plan observations.
Adjust ISO, f‑stop, shutter speed and see a simulated image brightness and depth of field effect. Learn manual mode.
Set up resources and processes and run the Banker's algorithm to check for safe states. Classic OS deadlock avoidance demo.
Enter a password and see the estimated time it would take to crack using brute force at different speeds. Educational.
Test SQL injection inputs on a mock database and see the resulting query. Learn how to prevent SQLi. No real data.
Enter an HTML snippet and see a rough transcription of what a screen reader might announce. Check alt texts.
Ask a yes/no question and click to reveal a classic Magic 8-Ball response. Animated shake effect. Nostalgic fun, pure local randomness.
Simulate memory page reference strings with FIFO, LRU, and Optimal algorithms. See page fault count. OS concept demo.
Upload an image and also see a UI mockup under different deficiencies side‑by‑side. Powerful for inclusive design.
Adjust page characteristics (image size, server delay, layout shift) and see the simulated Core Web Vitals scores. Understand what impacts performance.
Set launch angle, initial speed, and height. See the trajectory, max height, and range plotted on a canvas. Learn kinematics.
Keep track of a tennis match: points, games, sets, and deuce. Supports tiebreak. Great for friendly matches. Local.
Open many parallel WebSocket connections and send messages. Test your server's concurrency. All from your browser.
Visualize how aperture, focal length, and subject distance affect background blur. Interactive DOF calculator.
Set a cron expression and see a calendar of the next 1,000 execution times. Never miss a schedule again.
Select functional groups to see an approximate IR absorption spectrum. Learn spectroscopy visually. All local.
Adjust ISO, aperture, and shutter speed sliders and see how it affects the exposure of a sample scene. Learn photography basics.
Roll any number of dice thousands of times and see a live bar chart of the sum distribution. Great for game designers.
Simulate random mouse moves, clicks, or keystrokes to test idle‑timeout logic. Stops when you move the mouse. Dev test.
Fold a virtual square paper step by step with crease lines and visual previews. Practice origami basics without wasting real paper. All canvas‑based.
Type any CSS selector with :hover/:active/:focus and see the styles applied live. Perfect for debugging interaction states.
Control a lunar module and try to land softly on the moon. Manage fuel and thrust. Classic arcade physics. Canvas.
Watch the planets orbit the Sun in a top‑down 2D view. Adjust speed and zoom. Distances not realistic; beautiful model.
Drag to see how a solar eclipse occurs. Visualize the moon's shadow. Educational and interactive.
Simulate how images and UI elements appear to users with various types of color blindness. Upload or paste image URL. Promote inclusive design.
Upload any image and view it as a person with deuteranopia, protanopia, or tritanopia would. Promote inclusive design.
Select telescope and eyepiece parameters to see the field of view circle on a simulated night sky image.
Enter a URL and get a rough client-side performance simulation: request count, DOM size, and potential speed tips. No real Lighthouse.
Simulate rolling dice for board games, RPGs, and decision making. Choose number of dice and faces. Fun, lightweight, and no download required.
Flip a virtual coin to make a decision or settle a dispute. Realistic animation and fair random outcome. Simple, fast, and always available.