Why WebAssembly?

• Runs on every major platform:
  • Browsers: Chrome, Safari, Firefox.
  • Servers: Golang, Python, Node.js, C#, Java, Rust.
  • Edge: Cloudflare, Vercel, Fastly, Deno Deploy.
  • Mobile/Desktop: Swift on iOS/iPadOS/macOS & Java on Android.
• Web standard:
  • Well specced.
  • Backwards compatible.
  • Multiple competing implementations.
  • Many big players.
• Sandboxed:
  • Can’t read outside of its memory.
  • Calls to outside its system must be explicitly provided as ‘imports’.
  • If a WebAssembly instance traps, it won’t take down your whole system.
  • Can be CPU limited to run to a certain deadline or ‘fuel’ limit.
• Fast & light:
  • Can be interpreted quickly.
  • Can be just-in-time compiled to a particular CPU architecture.
  • Fast to instantiate.
  • Low memory footprint.
• Consistent:
  • Integer and floating-point math work exactly the same across all platforms.
  • Deterministic: Given the same module with the same inputs, the same output will be produced.
• Backwards-compatible:
  • A .wasm module authored today will still work in over a decade’s time.
  • Specification published by a W3C community group.