Comparing Rust vs. Zig: Performance, safety, and more

Editor’s note: This article was last updated by Eze Sunday on 4 June 2024 to include both languages’ memory management, including Rust’s borrow checker and Zig’s manual memory management, as well as to expand on the pros and cons of each language.

When you consider Rust and Zig, they make for a fascinating comparison. Both languages promote efficient, performant code, but they do so in different ways. They also both compile to a native binary that your system can execute directly.

These languages run on entirely different concepts and philosophies, affecting how developers code with them. With that in mind, let’s take a look at how well they measure up against each other.

What is Rust?

Rust is a general-purpose programming language that prioritizes efficiency, performance, and memory safety. It introduces a new way of programming that still allows developers to use some object-oriented and functional paradigms.

Coding with Rust requires an entirely different way of thinking centered around the ownership and borrowing rules that govern the language. While this way of thinking allows developers to write memory-safe and efficient code, it has a steep initial learning curve.

Let’s look at an example of Rust code:

fn main() {
    println!("Hello world");
}

In Rust, every executable starts from the main function, which is similar to other compiled programming languages. If you run the example above, you’ll get “Hello, World!” in your terminal.

Pros and cons of Rust

Like any programming language, Rust has its strengths and weaknesses. In this section, we’ll first explore the advantages that Rust offers to developers, followed by a discussion of the challenges and potential drawbacks.

Some benefits of Rust include:

• Difficult to leak memory: Rust’s ownership model makes it difficult to create memory leaks. The compiler enforces rules to ensure memory is properly managed and will throw an error during compilation if it is not
• Informative error messages: The Rust compiler provides very useful error messages when your code has errors, including suggestions for possible fixes. I find this to be a really interesting feature of Rust
• Performance: Rust’s zero-cost abstractions and low-level memory control ensure high efficiency and predictable performance
• Concurrency and parallelism: Rust has built-in support for parallel programming, along with features that ensure safe and efficient multithreading
• Memory safety without garbage collection: Rust uses an ownership and borrowing system to manage memory, providing safety and efficiency without the need for a garbage collector
• Cross-platform compatibility: Rust encourages cross-platform development, meaning you can easily generate builds for different platforms without significantly modifying the code
• Robust ecosystem: Rust has a strong ecosystem of tools and libraries — you can find most of them on the crates.io website. Its package manager, Cargo, significantly simplifies dependency management and integration with external libraries
• Interoperability: Rust provides robust Foreign Function Interface (FFI) capabilities, especially with C-lang and C++. The libc crate makes it a lot easier to talk to C-lang, providing all of the definitions necessary to easily interoperate with C code (or “C-like” code) on each of the platforms that Rust supports

Some drawbacks of Rust include:

• Initial learning curve: Rust is not inherently hard to learn, but it has an initial steep learning curve as it introduces a new way to think about programming
• Compile time: Rust isn’t fast in terms of compilation time, but that is mostly because it does all the work at compile time to ensure a safe and performant build
• Longer development time for new developers: Because of its emphasis on safety and accuracy with strict rules and explicitness, it might take a longer time for new developers. However, experienced Rust developers might not have this problem

Rust has reigned as the most desired programming language in Stack Overflow’s annual developer survey for 8 years in a row at the time of this writing.

Rust use cases

Now that you’ve seen what Rust can do, let’s take a look at places where it is already being used.

In systems programming, Rust is useful for tasks like building operating systems (support for Rust Linux kernel was merged in version 6.1 of the Linux kernel), device drivers, and embedded systems.

Both backend and frontend web developers also use Rust with popular frameworks like Rocket or Actix for backend development and Leptos, Dioxus, and Tauri for frontend development.

Rust is also used in networking like network protocols, proxies, load balancers, VPN software, and more.

Some more niche use cases for Rust include:

• Game development, with game engines like Amethyst and Bevy
• In blockchain and cryptocurrency, for developing smart contracts and blockchain networks in projects like Solana
• In the Internet of Things (IoT), for programming devices like microcontrollers and sensors

If you are looking to start using Rust right away, you can check out our guide to getting up to speed with Rust.

What is Zig?

Zig is a general-purpose, statically typed, and imperative, compiled system programming language. Zig was designed by Andrew Kelley to be a better version of C and the ability to interact with C code was an important consideration. Like Rust, Zig focuses on giving you the ability to write memory-safe, efficient, and fast software.

Let’s take a look at a hello world example written in Zig:

const std = @import("std");

pub fn main() void {
    std.debug.print("Hello, world", .{});
}

Also, like Rust, C, and C++, Zig doesn’t use a garbage collector. To achieve memory safety, Zig comes with mechanisms that promote memory safety, such as:

• Strict compile-time checks
• Optional types to handle potentially null values
• Explicit error handling with Error types
• Enhanced memory allocation with built-in allocators

Next, we’ll look at Zig’s pros and cons, as well as its use cases.

Pros and cons of Zig

Some of the benefits Zig offers to developers include:

• Faster compile time: Zig considers compilation time to be a serious issue; the team has been working hard to improve compilation. In fact, there is an ongoing proposal in favor of removing LLVM to boost compilation speed. Zig also leverages incremental compilation to build only the part of your code that was recently changed since the last build
• Cross–compilation: Zig includes built-in support for cross-compilation and makes it straightforward to compile code for different platforms without needing additional tools
• Control and low-level capabilities: Zig provides fine-grained control over memory and system resources, which is ideal for systems programming and scenarios requiring direct system resource management
• Safety features: Zig’s built-in allocators, defer statements, and the use of optional types help prevent common errors and improve code reliability by managing memory and ensuring safety without a garbage collector
• Simplicity and readability: Zig has a simple syntax and language design. This makes it easy to read, write, and maintain Zig programs
• Minimal external dependencies: Zig minimizes external dependencies needed to build and run programs, which simplifies development, enhances portability, and reduces the burden of managing dependencies across platforms
• Metaprogramming capabilities: Zig supports compile-time metaprogramming, which improves code flexibility and productivity by reducing boilerplate code and enabling compile-time checks and optimizations

Some of the drawbacks of Zig include:

• Memory leak flow: If you forget to deallocate memory, your memory will leak as there is no hidden control
• Learning curve: Understanding Zig may take time for new developers and developers unfamiliar with low-level programming concepts
• Limited ecosystem: The Zig language has a more miniature ecosystem than established languages because it is still in its early stages
• Maturity and tooling: Zig is a new language with room for improvement. However, note that there is still a strong and growing community around it
• Interoperability challenges: Zig provides C interfaces for compatibility, but integrating with other languages may require extra effort, such as managing data marshaling and communication between languages
• Learning availability: As the language is relatively new, there are not many learning resources available for complex use cases. But it’s growing gradually, and, as interest grows and adoption increases, there will be more resources available

Common Zig use cases

Zig has a wide array of use cases from system programming, web development, and embedded system programming.

One popular framework using Zig right now is the Bun runtime. According to the Bun website:

Bun is an all-in-one JavaScript runtime and toolkit designed for speed, complete with a bundler, test runner, and Node.js-compatible package manager.

Another use case is the Zig Language Server — a language server for Zig, which provides IDE features such as code completion and error checking, showcasing Zig’s utility in developing tools to enhance the development experience.

Like Rust, Zig also has a few more niche use cases:

• In game development due to its ability to support the creation of high-performance game engines, real-time simulations, and resource-intensive game logic
• In embedded systems and IoT for programming microcontrollers, sensors, and other resource-constrained devices
• In cryptographic applications for implementing encryption algorithms, digital signatures, secure communication protocols, and other security-sensitive components

If you’re interested in using Zig in your next project, take a look at our guide on getting started with Zig.

Memory management in both Rust and Zig

In this section, we’ll discuss memory management patterns for both Rust and Zig.

Memory management in Zig

Zig uses a manual memory management mechanism. It allows you the responsibility to allocate and deallocate memory safely and efficiently — with great power comes great responsibility. You have to be careful or, you might introduce a memory leak.

Here is a simple example of how the Zig memory allocator pattern works:

const std = @import("std");

pub fn main() !void {
    const allocator = std.heap.page_allocator;
    const buffer = try allocator.alloc(u8, 100); // Allocate 100 bytes
    defer allocator.free(buffer); // Ensure deallocation

    // Use the buffer
    buffer[0] = 42;
    std.debug.print("Buffer[0]: {}\n", .{buffer[0]});
}

In the above code, we initialize an allocator from the standard library’s heap module using page_allocator, which allocates memory in page-sized chunks. Then we went ahead to allocate 100 bytes to a buffer variable of u8 and also used the defer keyword to ensure that the allocated memory is deallocated when it goes out of its scope.

After allocating the memory, we then assign 42 to the first item in the buffer at index 0.

The language provides a variety of allocators and deallocators, which gives you the flexibility to manage memory according to the needs of your application.

Memory management in Rust

Memory management in Rust is handled by the borrow checker and the compiler, making it almost impossible to introduce memory leaks or use-after-free memory issues.

Here is a simple example to illustrate how the borrow checker works in Rust to help memory management:

fn main() {
    let mut vec = Vec::new(); // Create a new vector
    vec.push(42); // Push a value onto the vector

    // Borrowing the vector
    let first = &vec[0];
    println!("First element: {}", first);

    // Ownership and scope
    {
        let vec2 = vec; // Move ownership to vec2
        // vec can no longer be used here
    }
    // vec is now out of scope and deallocated
}

In the above code, we created an empty vector, pushed 42 into it, and then moved the vector to a new scope — literally transferring ownership to the new scope. As a result, we can’t use that vector again because it’s deallocated. The memory is tracked until it goes out of scope, at which point the memory is freed.

Rust vs. Zig: Similarities and differences

Now that we’ve looked at Rust and Zig individually, it’s time to put them together for comparison. It’s always interesting to compare different programming languages, especially when they have similar targets.

Let’s start with what they have in common:

• Memory safety: Rust and Zig prioritize memory safety and prevent common programming errors with strict compiler checks, static typing, and special rules that apply to each language
• Low-level control: Both offer more control over system resources, which makes them ideal for low-level tasks and systems programming
• Performance optimization: Both languages are known for their highly optimized code with manual memory management, direct CPU access, and compile-time evaluation
• Community and availability: Rust and Zig are open source projects with active communities, documentation, and tools
• No undefined behavior: Both programming languages have strict compiler checks and other features that prevent undefined behavior. This improves program stability and security by catching issues at compile time

Use the comparison table below to understand the differences between Rust and Zig:

Feature	Rust	Zig
Memory safety	Rust uses its strict ownership and borrowing rules to ensure that any code a developer writes is safe and the chance of memory leak is reduced.	Zig allows the developer the responsibility of allocating and deallocating memory properly. This method is prone to errors as the compiler won’t complain if you don’t deallocate memory.
Syntax	Rust has an expressive syntax that borrows similarities from several languages and it also introduces a lot of it’s own domain specific syntax like how it handles lifetimes and borrowing	Zig uses a simple and approachable language syntax. You’ll likely understand what is going on by just looking at the code even if you are new — at least that was how it was for me.
Ecosystem	Rust offers a robust ecosystem, including libraries, tools, and community support	Zig is a newer language, and while it doesn’t have a large ecosystem of tools, its toolchain is solid.
Interoperability	Rust has decent FFI compatibility. It works well calling Rust functions from C but it can be challenging to call C functions from Rust.	Zig has a superior FFI. It works well calling C functions from Zig and calling Zig functions from C.
Error handling	Rust uses Result and Option types for explicit error handling	Zig uses error types, error unions, and deferred statements for error handling.
Package manager	Rut uses cargo package manager for handling packages and dependencies.	Zig uses its built-in package manager for handling packages and dependencies.

Besides their similarities and differences, we can compare Rust and Zig in three other ways: performance, popularity, and how much their programmers are paid. Let’s take a closer look.

Rust vs. Zig: Performance

Objectively, between Rust and Zig, there is no absolutely better-performing language. Rust may outshine Zig in certain areas, while Zig outperforms Rust in others.

Let’s closely examine each performance with a comparison from the programming languages and compiler benchmarks:

This benchmark project contains programs written in several programming languages that run simultaneously. The outcomes from their runs are then measured and presented in a tabular form for you to see how each programming language performs in the task.

In the image above, we have the mandelbrot and nbody programs, both written using Rust and Zig. The measurements in the comparison tables are arranged from more performant to less performant.

You’ll notice that in some cases, Zig performs better than Rust, and in others, Rust performs better than Zig. Both are highly performant languages, so either option should serve you well in your projects.

Rust vs. Zig: Popularity

When picking a programming language to learn, popularity can be a significant factor to consider. Choosing a popular language not only increases your chances of finding resources and support but also means you’ll have a higher chance of finding developers to collaborate with.

Stack Overflow’s latest developer survey provides some interesting insights. As mentioned earlier, Rust has been the most admired language for 8 years in a row including 2023, with over 84 percent of respondents saying they want to use it again compared to Zig’s 71 percent.

Rust is also 14th on the list of popular languages, while Zig is farther behind at number 41 out of 51 total languages listed.

Zig’s lower popularity in both cases may be because it’s still in its early stages. Either way, it’s crucial to consider the popularity of the language you choose to work with.

Rust vs. Zig: How much do they pay?

The Stack Overflow developer survey also contains information about the top-paying technologies as reported by the respondents. You may find this chart helpful, especially if you’re considering learning either Rust or Zig.

Interestingly, despite being a new addition, Zig is actually the highest-paid language to know in 2023 survey, while Rust is 14th on the list:

While the chart is a good starting point, there are other factors to consider when determining how much a developer gets paid, such as their experience level and the company they work for.

Conclusion

Regarding Rust and Zig, it’s hard to say which is the clear winner. Each language has strengths and weaknesses that make them fair competitors. I hope this article was useful in helping decide which language to use for your project.

Thanks for taking the time to read! If you have any questions about either language, feel free to comment below.