A multi-language code editor: the Ace editor switches syntax mode with the language you pick (HTML, CSS, SCSS, JavaScript, JSX, TypeScript, TSX, JSON, YAML, Markdown, XML, GraphQL, Python, SQL, shell, PHP, Java, Go, Rust, Ruby, C#, C/C++). Run formats the code in the Worker — Prettier for JS/TS/CSS/GraphQL, JSON, YAML and SQL formatters — or exports it as static highlighted HTML; either way you get line/word/byte counts, indentation and line-ending detection, trailing whitespace, TODO markers and light per-language notes (loose equality, var, debugger, PEP 8 tabs, SELECT *, missing alt, invalid JSON). The preview shows the highlighted code. Everything runs locally.