What Is Rust? The Programming Language Explained

Rust is an open-source programming language built for writing fast, low-level software — operating systems, browsers, game engines, command-line tools — without the memory bugs that have historically plagued languages like C and C++. (This is the programming language, not the survival video game or the Rust-Oleum paint brand that share its name.)

What Is Rust?

According to the Rust Project's own documentation, the Rust Book, Rust is "a systems programming language that runs blazingly fast, prevents segfaults, and guarantees thread safety." It started as a personal project by Mozilla engineer Graydon Hoare in 2006, became an official Mozilla-sponsored project in 2009, and reached its first stable 1.0 release in May 2015. Since February 2021, the language has been stewarded by the independent, nonprofit Rust Foundation rather than any single company.

Rust compiles to native machine code, like C and C++, which is why it's grouped with them as a systems language rather than compared to interpreted languages like Python. That means Rust programs typically run with performance close to C/C++, without a virtual machine or runtime garbage collector sitting in the way.

Memory Safety Without a Garbage Collector

The feature Rust is best known for is its ownership system. In most systems languages, a programmer manually allocates and frees memory, and getting that wrong — freeing memory twice, using it after it's freed, or two parts of a program fighting over the same data at once — is the root cause of a huge share of real-world crashes and security vulnerabilities. Languages like Java, Python or Go solve this with a garbage collector that automatically cleans up unused memory while the program runs, at some cost to performance and predictability.

Rust takes a third path. Its compiler, not a runtime process, enforces a set of ownership and "borrowing" rules: every value has exactly one owner, and the compiler tracks when that owner goes out of scope and automatically inserts the code to free the memory at that exact point — no garbage collector required. If code tries to use a value after its owner has gone out of scope, or lets two parts of a program both try to modify the same data at the same time without synchronization, the Rust Book is explicit that this is treated as a compile-time error: the program won't build until the conflict is resolved. The tradeoff is a steeper learning curve — Rust's compiler is famously strict, and new users often spend real time satisfying it — in exchange for ruling out entire categories of bugs before the program ever runs.

What Is Rust Used For?

Per the Rust Book and the language's own site, Rust is commonly used for:

• Systems and embedded programming — operating system components, device drivers and embedded firmware, the traditional home turf of C.
• Command-line tools — Rust's combination of speed and a rich package ecosystem (via Cargo, covered below) has made it popular for CLI utilities.
• WebAssembly — Rust has first-class, official support for compiling to WebAssembly, letting Rust code run inside web browsers at near-native speed.
• Parts of major browsers — Mozilla originally created Rust to safely rewrite performance-critical, memory-sensitive components of the Firefox browser engine.
• Networking and backend services — Rust's speed and safety guarantees suit software that needs to be both fast and resistant to the memory-corruption bugs that often become security vulnerabilities.

Where Rust Is Used Today

Rust's original purpose was defensive: Mozilla created it to let engineers rewrite performance-critical, memory-handling pieces of the Firefox browser engine without reintroducing the C++ memory bugs those components had shipped with before. That browser-engine use case is still one of the clearest real-world proofs of what Rust is for — code that has to run fast, handle untrusted input, and not crash or create a security hole when that input is malformed.

The language's reach has grown well beyond browsers since then. The Linux kernel began formally accepting Rust code alongside its long-standing C codebase starting with kernel version 6.1 in December 2022 — a significant milestone, since the kernel had used C almost exclusively for three decades, and the change was made specifically to use Rust's compile-time safety checks for new driver code. Rust's own annual community survey has also tracked adoption climbing year over year, with a large and growing share of surveyed organizations reporting they use Rust in production and would choose it again.

Rust vs. C and C++

Rust doesn't replace C or C++ in every context — mature C/C++ codebases, highly specialized compilers, and some embedded platforms still favor the older languages — but for new, security-sensitive systems code, Rust's compile-time guarantees are why organizations including Microsoft, Google and Amazon have each published engineering posts about adopting it for parts of their own infrastructure.

Against higher-level, garbage-collected languages like Go or Python, the comparison runs the other way: Rust asks more of the programmer up front — satisfying the borrow checker takes practice — in exchange for predictable, native-speed performance with no garbage-collector pauses. Python and Go both trade some raw performance and memory control for faster day-to-day development, which is why they remain the more common choice for scripting, data work and many backend services where Rust's stricter guarantees aren't the deciding factor.

How Rust Handles Errors (No Null, No Exceptions)

Rust also departs from most mainstream languages in how it represents failure. Rather than a null reference that can crash a program the moment it's used unexpectedly — a pattern so common in other languages that its own inventor, Tony Hoare, has called null references his "billion-dollar mistake" — Rust has no null value at all. Instead, the Rust Book describes an Option type that is explicitly either Some(value) or None, and the compiler forces code to handle both cases before it will build, so a missing value can't silently slip through unchecked the way a null pointer can.

Rust handles recoverable errors the same explicit way, through a Result type that's either Ok(value) on success or Err(error) on failure, instead of the try/catch exception handling used by languages like Java, Python or C++. A function that can fail returns a Result, and calling code has to explicitly deal with the possibility of an error — there's no way to accidentally let an exception propagate silently past a layer of code that wasn't written to expect it. Rust does still support panics for genuinely unrecoverable situations, but the Book's guidance treats Result as the default for anything a program could reasonably recover from.

Cargo and the Rust Toolchain

Cargo is Rust's built-in build system and package manager, bundled with every standard Rust installation. It compiles your code, downloads and manages external libraries (called "crates") from the public registry at crates.io, and runs your project's tests — all through one consistent command-line tool, which is part of why Rust's tooling is frequently cited as a strength relative to older systems languages that lack a single standard package manager.

To actually get Rust installed, the Rust Project's official guidance points to rustup, a command-line tool that installs and manages Rust versions and the associated tools (including Cargo) from one script, and makes it straightforward to switch between stable, beta and nightly releases of the compiler.

Cargo's role is similar to what Docker does for shipping an application with its dependencies, or what a container orchestrator like Kubernetes does for running many of them — each tool standardizes one part of getting code from a developer's machine into a working, repeatable build, just at a different layer of the stack.

Is Rust Hard to Learn?

Rust is widely described as having a steeper initial learning curve than languages like Python, JavaScript or TypeScript, mostly because of the ownership and borrowing rules described above — the compiler will refuse to build code that a C or Python programmer might expect to just work. The Rust Project's response to that reputation has been heavy investment in its own documentation: the free, official Rust Book is written specifically to teach ownership concepts from first principles, and the compiler itself is designed to produce detailed error messages that explain what rule was broken and how to fix it, rather than a bare error code.

A typical first stumbling block looks like this: code that tries to read a variable after its value has been "moved" elsewhere won't compile, with an error pointing at exactly which line took ownership. Experienced Rust developers describe this as frustrating for the first few weeks and then, once the ownership model clicks, as a tool that catches entire classes of bugs other languages would only surface at runtime — or not at all, until they reached production.

How to Get Started With Rust

1. Install Rust via rustup — the official installer, available from rust-lang.org, sets up the compiler (rustc), Cargo and related tools together.
2. Start a new project with cargo new my_project, which scaffolds a ready-to-build project folder.
3. Read the Rust Book — the free official guide at doc.rust-lang.org/book is the Rust Project's own recommended starting point and covers ownership, the type system and Cargo in order.
4. Build and run with cargo run, which compiles the project and executes it in one step.

What's Next

Rust's combination of C/C++-level performance with compile-time memory safety is why it has moved from a Mozilla side project into infrastructure at major cloud providers, browser engines and operating systems over the past decade, now stewarded independently by the nonprofit Rust Foundation. The language also ships periodic "editions" (2015, 2018, 2021, 2024) that let new conventions and syntax ship without breaking existing code written against an older edition — a project opts into a new edition deliberately rather than being forced onto it by a compiler upgrade.

If the ownership model sounds unfamiliar, the official Rust Book remains the most direct way to see it in action: it's free, written by the language's own maintainers, and built around the same compiler error messages you'll actually encounter learning the language.

Written byFelix Moreau

Felix Moreau writes Pandromeda's software coverage and how-to guides. He covers Windows, macOS and Linux updates, the apps people rely on, emulators and developer tools, and turns official documentation into clear, numbered steps that work on the current version.

More from Felix MoreauAll Software & Guides coverage