Introduction

Welcome to the SwiftWasm Documentation!

WebAssembly is described on its home page as:

WebAssembly (abbreviated as Wasm) is a binary instruction format for a stack-based virtual machine. Wasm is designed as a portable compilation target for programming languages, enabling deployment on the web for client and server applications.

We use LLVM as a compiler backend to produce WebAssembly binaries. Our resulting binaries also depend on WASI, which is a modular system interface for WebAssembly. WASI is mainly required to compile Swift Standard Library.

Important note

In 2024, Apple introduced Swift Embedded. While both projects benefit from each other, it is important to understand that they are different targets at the build phase, consequentially with different sets of abilities. Embedded Swift very limited but can produce small binaries. Example.

Project Status

All compiler and standard library changes have been upstreamed to the official Swift repository, and the upstream CI is now testing WebAssembly targets.

The remaining works are:

• Integrating the build system with the official Swift CI.