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Server Mode

Wasmrun's server mode (wasmrun run) compiles and serves WebAssembly projects with a built-in development server, live reload, and browser-based execution.

What It Does​

Server mode is a development tool that:

  1. Detects your project language (Rust, Go, C/C++, Python, AssemblyScript)
  2. Compiles source code to WebAssembly using the appropriate plugin
  3. Serves the compiled .wasm file via a local HTTP server
  4. Opens a browser UI showing your module's exports, memory layout, and execution
  5. Watches for file changes and auto-recompiles (with --watch)
wasmrun run ./my-rust-project --watch

When to Use​

  • Developing WebAssembly modules that target the browser
  • Testing wasm-bindgen projects with JavaScript glue
  • Iterating on WASM libraries with instant feedback
  • Inspecting module structure (exports, memory, sections) in a visual UI

Quick Example​

# Compile and serve a Rust WASM project
wasmrun run ./examples/rust-hello

# Serve a pre-built WASM file
wasmrun run ./output.wasm

# With live reload
wasmrun run ./my-project --watch --port 3000

The server starts at http://localhost:8420 by default, serving an HTML page that loads and runs your WASM module.