Everything in the catalog

Extract pages or ranges from a PDF locally in your browser.

Run a real Postgres compiled to WebAssembly in the browser and try SQL against it.

Converts images, audio, video and documents locally in the browser using WebAssembly.

Linux virtual machine that runs in the browser through WebAssembly.

Searchable list of emojis with meanings, used to label commit messages by intent.

Try ESLint and TypeScript-ESLint rules and inspect the AST in the browser.

Interactive Python console that runs CPython compiled to WebAssembly inside the page.

Turns a Git repository into one text digest of its code and structure for pasting into an LLM.

Online LaTeX editor with collaboration, templates and version history, so no local install is needed.

HTML5 internet speed test that measures download, upload, ping and jitter.

Open-source whiteboard combining mind maps, flowcharts and freehand drawing on an infinite canvas.

Demo UI of sql.js, SQLite compiled to JavaScript, for running queries on in-memory databases.

Try the Papa Parse CSV parser on pasted or uploaded text and see the parsed rows and config effects.

Demo of the Editor.md Markdown editor with live preview, toolbar, TeX math and flowchart support.

Matches each part of a shell command with the manual-page text that explains it.

Generates typed models in many languages from JSON, JSON Schema or GraphQL samples.

Public HTTP request and response service for testing clients, with endpoints for headers, status codes and delays.

Sliding tile puzzle where matching numbers merge until you reach 2048.

Markdown editor with themes tuned for WeChat articles, copying rendered output with styles.

Drag-and-drop recipe builder that chains hundreds of operations for encoding, encryption, compression and data analysis.

Official PlantUML web server where you type UML text and get the rendered diagram with shareable URL.

Paste Markdown headings and lists and get an interactive mind map you can export.

Train a tiny neural network on toy datasets in the browser and watch the decision boundary form.

Sprite and pixel-art editor with animation frames, exporting GIF, PNG sprite sheets and more.