HTML Tools

Build single-file HTML applications that combine HTML, JavaScript, and CSS into one portable file. These tools solve specific problems, load instantly, require no build step, and can be hosted anywhere as static files.

This skill codifies patterns from building 150+ such tools. The goal is always: one file, no build step, no framework overhead, maximum utility.

When to Use This Skill

Use this when the user wants a utility or tool — something interactive that transforms, displays, debugs, converts, or processes data. Common types:

• Converters (JSON↔YAML, Markdown→HTML, CSV→table, format transformers)
• Viewers/Inspectors (clipboard contents, EXIF data, keyboard events, CORS checks)
• Processors (image croppers, OCR, diff generators, text transformers)
• API-powered tools (calling CORS-enabled APIs like GitHub, PyPI, Bluesky, iNaturalist)
• LLM-powered tools (calling OpenAI/Anthropic/Gemini APIs directly via CORS)
• Developer utilities (regex testers, color pickers, encoding tools, hash generators)

If the user wants a polished marketing page or portfolio, use the frontend-design skill instead.