The Origins of Rust: A Side Project That Rewired Systems Programming

For about forty years, if you needed software that was fast and close to the hardware, you wrote it in C or C++. You also accepted a tax: whole categories of bugs around memory, the kind that cause crashes and security holes, were yours to catch by hand, and humans are bad at catching them. Rust is the first language in a long time to argue that you can have the speed without the tax, and to make the argument convincing enough that Amazon, Microsoft, Google, and the Linux kernel all signed on.

A personal project with an odd name

Rust started around 2006 as a side project by Graydon Hoare^[1], then an engineer at Mozilla. The story he has told is that the name came from rust fungi, a group of plant pathogens that are remarkably robust and overbuilt for survival. He has also pointed to the plain connotation of rust as something humble and everywhere. Either way, it was a personal experiment, not a corporate initiative.

Mozilla began officially sponsoring the work in 2009, and the project went public in 2010. Mozilla's interest was practical. Browsers are enormous C++ programs, and C++ memory bugs are a steady source of the security vulnerabilities that make browsers dangerous. A language that kept the performance but removed the most common bug classes would be worth a great deal to a company whose main product was a browser.

The language that got smaller before it got stable

Early Rust looked quite different from the language people use now. It had a garbage collector, lightweight green threads, a feature called typestate, and other ideas that were later cut. The years before the first stable release were spent removing things as much as adding them. The team kept narrowing in on a single powerful idea and letting the rest go.

That idea is ownership. In Rust, every value has exactly one owner^[2], and the compiler tracks how long each value lives and who is allowed to read or write it at any moment. You can lend out references, but the rules about borrowing are checked at compile time by a component called the borrow checker^[3]. If your code could lead to a dangling pointer, a double free, or two threads writing the same data at once, the program does not compile. There is no garbage collector doing this at runtime, so you pay no runtime cost for the safety. You pay an upfront cost instead: you have to satisfy the borrow checker, and learning to do that is the famous hard part of Rust.

Servo, and a proving ground

Mozilla did not just fund a language. It funded Servo, an experimental browser engine written in Rust^[4], meant to prove that the language could handle one of the most demanding workloads in software and to pressure-test the ideas under real conditions. Parts of Servo later made their way into Firefox through a project called Quantum^[5], which shipped Rust code to hundreds of millions of users and gave the language credibility it could not have bought any other way.

Rust reached its 1.0 release on May 15, 2015^[6], along with a strong promise: code that compiles on a stable release should keep compiling on future stable releases. For a systems language competing with C and C++, that stability guarantee mattered as much as any feature.

Cargo, editions, and the parts people actually love

A language is only as good as the day-to-day experience of using it, and Rust paid unusual attention to that. Cargo, its build tool and package manager^[7], handles dependencies, builds, tests, and publishing to the central registry, crates.io, with a consistency that programmers coming from C and C++ found startling. The compiler's error messages are written to teach, often pointing at the exact problem and suggesting the fix.

Rust also introduced editions, in 2015, 2018, and 2021^[8], which let the language make opt-in changes to syntax and idioms without breaking old code. A crate declares its edition, and editions interoperate, so the ecosystem can move forward without a painful split of the kind that divided other language communities. Surveys reflected the result. Rust was voted the most loved or most admired language in the Stack Overflow developer survey for many years running, starting in 2016^[9].

From Mozilla to a foundation

The institutional story took a sharp turn in 2020, when Mozilla laid off staff, including people who worked on Servo and Rust. Rather than leave the language dependent on a single struggling sponsor, the community and industry created the Rust Foundation in 2021, backed by companies including Amazon Web Services, Microsoft, Google, Huawei, and Mozilla. Rust stopped being a Mozilla project and became an independent one with broad corporate support, which is a healthier place for critical infrastructure to sit.

Why a systems language belongs on a web blog

You might reasonably ask what a language built for operating systems and browser engines is doing in a discussion of web development. The answer is that Rust quietly became part of the web's foundation.

The first reason is WebAssembly, a compact binary format that runs in the browser at near-native speed^[10]. Rust is one of the best languages for producing WebAssembly, which lets you run computationally heavy code, image processing, parsers, games, cryptography, directly in the browser alongside JavaScript. The second reason is tooling. A new generation of web build tools is written in Rust because startup time and build speed matter at scale. Turbopack, the swc compiler, Biome, and others are Rust programs that front-end developers use every day without thinking about the language underneath. The third reason is the back end, where frameworks like Actix and Axum let teams write fast, safe web services, and where the Deno runtime is itself built in Rust^[11].

What it means today

Rust now runs in Firefox, in Amazon's Firecracker virtualization that powers serverless computing^[12], in parts of Windows, at Cloudflare and Discord and Dropbox, and inside the Linux kernel, which began accepting Rust code in 2022^[13] after decades of being C only. That last one is the clearest signal of all. The most conservative, most scrutinized codebase in the world decided the memory-safety argument was worth a second language.

A side project with a name borrowed from a fungus turned into the language that convinced the industry it did not have to choose between speed and safety. For the web, it shows up as faster tools, heavier work running in the browser, and back ends that are hard to crash. You do not have to write Rust to benefit from it. A growing share of the web already runs on it.