C# beautifier - format C# in your browser with the real clang-format
C# gets a full reformat in the browser, not just an indent fix. Under the hood it runs **clang-format** (with the Microsoft style preset (Visual Studio default)) - the original compiler-grade formatter compiled to WebAssembly. The same one you use in the terminal or in CI.
What this means in practice: it wraps long lines (100 chars by default), normalises indentation (tab / 2 / 4 spaces - your pick), normalises spacing around operators, aligns function arguments, respects the language's idiomatic conventions (`if (x)` vs `if(x)`, etc.). Exactly what `Format Document` does for C# in VS Code with the official extension.
Accepts .cs files. Everything runs in your browser - the code never leaves your machine, no upload, no server-side logs. The WASM blob lazy-loads on the first click (60-300 kB), subsequent formats are instant.
For C# we use the Microsoft preset in clang-format: Allman braces (each `{` on its own line), 4-space indent, switch-case indent - i.e. exactly what Visual Studio gives you with the default `.editorconfig`. It handles LINQ (`from x in xs select x`), async/await, records, pattern matching (C# 9+).
How to use it
- Pick a mode (Gentle / Aggressive / Cosmetic-only) or keep the default.
- Paste your code into the left panel, or use "Upload file".
- Tune settings (gear icon): indent, width, quotes, semicolons.
- Click Format - first click takes a moment (libraries lazy-load).
- On the right you get the output with syntax highlighting - copy, download, or open in new tab.
When this is useful
Five typical C# situations:
- Pretty-print a messy source. Code you pasted from a colleague / a PDF / a blog post has broken indentation. clang-format does a full reformat in a second.
- PR review. The team uses a consistent style - clang-format enforces the official style of the language, so code review stops shouting about whitespace.
- Convert tabs to spaces (or back). One project's `.editorconfig` says 4 spaces, another says 2 - switch in the settings popover.
- Sanity-check syntax. If clang-format rejects the code with a parse error you have a syntax typo - a quick sanity check before kicking off a build.
- Syntax-highlighted preview. After formatting you get a coloured preview (powered by Shiki, the same TextMate grammars VS Code uses).