Rust vs WebAssembly: What are the differences?

Introduction

WebAssembly (Wasm) and Rust are both used in web development, but they have key differences that set them apart. Understanding these differences can help developers choose the right tool for the job.

1. Low-Level vs High-Level Language: Rust is a low-level programming language that allows developers fine-grained control over system resources. On the other hand, WebAssembly is a binary instruction format that is designed to be executed at a low level by running it in a virtual machine. This means that Rust can be used to write low-level code directly, while WebAssembly is more suited for running code compiled from higher-level languages.

2. Safety and Performance: Rust has a strong focus on safety and memory management. It uses ownership, borrowing, and lifetimes to ensure memory safety without requiring a garbage collector. This leads to highly performant code with fewer runtime errors. WebAssembly, on the other hand, provides a sandboxed execution environment that protects the host environment from potentially malicious code. While it offers memory safety compared to JavaScript, it doesn't have the same level of control that Rust provides.

3. Language Flexibility: Rust is a general-purpose programming language that can be used for a wide variety of applications beyond web development, such as systems programming or game development. WebAssembly, on the other hand, is designed specifically for web applications and can be used alongside other web technologies like HTML, CSS, and JavaScript. While Rust can target WebAssembly as a compilation target, WebAssembly is not limited to Rust.

4. Native vs Portable: Rust code can be compiled into machine code that runs directly on the underlying hardware, providing maximum performance. WebAssembly, on the other hand, is designed to be portable and platform-independent. It can be executed in various environments like browsers, servers, or even embedded devices, ensuring that the code behaves consistently across different platforms.

5. Tooling and Ecosystem: Rust comes with a rich set of tooling and a growing ecosystem of libraries and frameworks. It has its package manager (Cargo) and a strong community that actively contributes to its development. WebAssembly, being a binary format, can be used with different programming languages and has its own set of tools and frameworks. However, the tooling and ecosystem for WebAssembly are still evolving and not as mature as Rust's.

6. Compilation and Execution: Rust code is compiled using the Rust compiler (rustc) into machine code or WebAssembly. The resulting binary can then be executed on the target device or platform. WebAssembly, on the other hand, is designed to be a compact binary format that can be loaded and executed quickly in a web browser or another runtime environment. It provides a standardized format that can be efficiently executed across different platforms.

In summary, Rust is a low-level, memory-safe language with a focus on performance and control, while WebAssembly is a portable binary format that enables running code in a sandboxed environment. Rust offers more extensive tooling and flexibility beyond web development, while WebAssembly provides a standardized format for executing code across platforms.