Playgrounds

Real-time Jinja2 sandbox with filters, loops, and zero server execution.

Real-time client-side frontend sandbox with live iframe rendering, console logging, and instant export.

Execute modern ES2024 and TypeScript in sandboxed thread. Live console logs and execution benchmarks.

Execute real Python 3.12 in WebAssembly (Pyodide). Standard libraries included. Zero server execution.

In-browser SQLite WebAssembly memory database. Run joins, window functions, and export CSV/JSON.

Lightweight Lua 5.4 in WebAssembly (Fengari). Test tables, metatables, and closures.

Live Markdown editor with Mermaid diagrams, LaTeX math, and HTML/MD export.

Live HTML table preview from JSON. Copy as Markdown, TSV, or raw HTML.

Live speech transcription via the Web Speech API. Chrome/Edge only, multiple languages, interim + final results.

Postman-class browser client for REST, GraphQL, and gRPC-Web / Connect with collections, environments, and pm.* test scripts.

Track daily clock-in/out shifts across midnight with unpaid breaks, overtime thresholds, and gross pay tally.

Drift-free Pomodoro focus timer with custom intervals, Web Audio chime, desktop alerts, and local session tally.

Millisecond-accurate stopwatch using performance.now() with split laps, average delta analysis, and CSV export.

Accurate event countdown with IANA timezone conversion, working-day calculations, elapsed-time tracking, and shareable links.

Interactive HTML5 canvas decision wheel with cryptographic randomness, custom weights, spin history, and presets for standups, meals, and dice.

Searchable emoji browser with skin tone modifiers, Unicode codepoints, HTML entities, and UTF-8 byte sequences.

Multi-note browser scratchpad with hashtags, live Markdown preview, JSON backup and restore, and localStorage persistence.

Step-by-step interactive visualizer for Sorting, Searching, Linked Lists, Stacks, Queues, Binary Search Trees, Heaps, and Graph Traversals.

Click-to-plot interactive visualizer for Linear & Logistic Regression, k-NN, k-Means Clustering, Naive Bayes, and feature normalization, with formulas and step-by-step explanations.

Reference guide for all 12 English verb tenses across past, present, and future with interactive affirmative, negative, and question conjugator.

Design system architectures, sequence flows, and state machines in ASCII and Unicode box drawing. Export to Markdown or SVG.