Playground
Small interactive web experiments — built to learn, demo, and tinker. Everything runs on-device.
Systems & CS
TCP Latency Lab
A real sliding-window transport sim — tune RTT, loss, jitter, bandwidth and window size, and watch throughput, retransmits and bufferbloat respond.
Protocol sim · CanvasTLS Handshake Lab
Watch the TLS handshake over an adjustable-latency link — 1.2 vs 1.3 vs 0-RTT — and see why round trips dominate time-to-first-byte.
Protocol sim · CanvasConsistent Hashing
The ring behind distributed caches and sharded databases — add/remove nodes, tune virtual nodes, and watch keys remap and load rebalance.
Distributed systemsQuorum Lab
A leaderless (Dynamo-style) cluster — tune N, R and W, fail nodes, and see how R + W > N buys consistent reads, and what goes stale when it doesn't.
Distributed systemsRaft Consensus Lab
Leader-based consensus, live — randomized timeouts elect a leader, a log replicates entry by entry. Kill the leader, split the network, watch it heal.
Distributed systemsCache Eviction Lab
LRU vs LFU vs FIFO vs Belady's optimal on one access stream — dial cache size and skew, and watch the hit rates pull apart.
Systems simPathfinding
Draw walls and watch BFS, Dijkstra and A* race to the goal — the frontier expands, then the shortest path snaps into place.
AlgorithmsSorting Visualizer
Bubble, insertion, merge, quick, heap — race the classic sorts on a bar chart with sound, and watch comparisons and swaps tick up.
AlgorithmsNeural Net Playground
A tiny neural network trained live in your browser — pick a dataset, add layers, and watch the decision boundary form as the loss drops.
Machine learningDeveloper tools
JWT Decoder
Paste a JSON Web Token and read its header and claims decoded — expiry, issuer, audience — with a valid/expired badge. On-device, nothing sent.
Dev toolRegex Tester
Live-test a regular expression against your text — every match highlighted, capture groups listed, with a cheatsheet and example patterns.
Dev toolEncoder & Hash
Base64, URL, hex and HTML entity encode/decode, plus SHA-1/256/384/512 hashes — all computed live in the browser.
Dev tool · Web CryptoCIDR Calculator
Type an IPv4 + prefix and get the network, broadcast, host range, masks and binary split instantly — plus subnet splitting and membership checks.
NetworkingQR Generator
Turn a URL, Wi-Fi login, contact or any text into a scannable QR code — pick error correction and colors, download PNG or SVG. Encoder is self-contained.
Dev toolTOTP Generator
Live authenticator codes from a Base32 secret — countdown ring, time offset, previous/next codes, and a QR you can scan to program a device.
Web Crypto · QRWhat's My IP
Your public IP resolved at the CloudFront edge, plus user agent, OS, screen, timezone, and a live ping.
Edge function · Client infoID Barcode Reader
Scan or photograph the PDF417 barcode on the back of a US driver's license and read the decoded fields — all on-device, nothing uploaded.
Camera · PDF417Graphics & art
Fluid Simulation
A real-time GPU fluid — drag to inject swirling, diffusing dye. Stable-fluids Navier–Stokes in raw WebGL.
WebGL · ShaderFractal Explorer
Dive into the Mandelbrot set on the GPU — drag to pan, scroll or pinch to zoom deep, switch palettes, or flip into Julia mode.
WebGL · ShaderPond
A WebGL point-cloud water surface with real ripple physics — disturb it with your mouse or finger and watch waves propagate and reflect.
three.js · WebGLFourier Epicycles
Draw a shape and watch a chain of rotating circles redraw it — the Fourier transform made visible. Slide the harmonics for rough-to-faithful.
Canvas · MathDouble Pendulum
A physically accurate double pendulum — drag, release, and watch chaos unfold. Toggle near-identical copies to see them diverge.
Physics · CanvasGame of Life
Conway's classic cellular automaton — draw cells, stamp a glider gun or pulsar, and watch age-colored patterns evolve, breed, and die.
Canvas 2DSpin Art
Pour paint onto a spinning disc and watch it smear into hypnotic spirals. Dial in the speed, brush, and colors, then save your masterpiece.
Canvas 2DMusic & audio
Modular Synth
A patchable Web Audio synth — wire oscillators, filters, an LFO and effects with virtual cables, then play it with your mouse or keyboard.
Web Audio APIBeat Sequencer
A 16-step drum machine with synthesized kick, snare, hats and more — toggle the grid, set tempo and swing, and watch the playhead run.
Web Audio APISpectrogram
Point your mic at the world and watch a live scrolling spectrogram — frequency, time, and loudness in color, with an instant spectrum and peak note.
Web Audio · FFTGames & toys
2048
Slide and merge tiles to reach 2048 — arrow keys or swipe, with undo, best-score saving, and smooth tile animations.
GameMinesweeper
The classic — reveal cells, flag the mines, and don't blow up. Beginner to Expert, a safe first click, tap-and-long-press on mobile.
GameTyping Speed Test
Type the passage as fast and cleanly as you can — live WPM, accuracy and errors, with a results summary and fresh passages.
Toy