Skip to content

What Rust Is

Scope: what the language is, where it's used, and whether it's worth your time. Not a tutorial — that starts with Your First Program.

The one-sentence version

Rust is a programming language that runs as fast as C, but the compiler refuses to build programs with certain kinds of memory bugs.

The problem it solves

Most languages pick one side of a tradeoff:

Approach Example Cost
Trust the programmer C, C++ Memory bugs: crashes, security holes
Watch at runtime Python, Java, Go Garbage collector pauses, slower, more memory

Rust takes a third path: check at compile time. The compiler tracks which part of your program owns each piece of memory, and rejects code that could use memory after freeing it, free it twice, or let two threads fight over it. No garbage collector running in the background. The checking happens once, when you build.

The practical effect: whole categories of bugs become compile errors instead of mystery crashes at 2 AM.

Where Rust actually lives

  • Operating systems: parts of the Linux kernel and Windows kernel are now written in Rust; Android uses it for security-critical components.
  • Browsers: Firefox's CSS engine (Stylo) is Rust.
  • Infrastructure: Cloudflare, Discord, and Dropbox run Rust in performance-critical backends.
  • Developer tools: ripgrep (fast file search), uv (fast Python package installer), and much of the modern Rust-adjacent toolchain are Rust programs.
  • Embedded: microcontrollers, where there's no room for a garbage collector.
  • WebAssembly: Rust compiles well to WASM for browser-side speed.

What Rust is not

  • Not a scripting language. There's no REPL-style workflow like Python's. You write a file, compile it, run it. The cycle is fast, but it's a compiled language.
  • Not garbage-collected. There's no background cleaner. Memory is freed at predictable, compiler-determined points.
  • Not object-oriented in the Java sense. No classes, no inheritance. It has structs, traits (shared behavior), and enums — closer to "data plus functions" than to class hierarchies.
  • Not easy at first. The borrow checker (covered in Ownership and Borrowing) rejects code that looks fine. Expect a few weeks of friction. This is normal and temporary.

Should you learn it?

Worth it if you:

  • Write or maintain C/C++ and want fewer memory bugs
  • Build CLIs, servers, or embedded firmware where speed matters
  • Want to understand what "memory safety" actually means, concretely

Probably overkill if you:

  • Mostly glue APIs together in Python or JavaScript
  • Need a quick script this afternoon (use Python)
  • Want the gentlest possible first language (Python is still that)

Check

You can explain, in your own words:

  • [ ] What the borrow checker checks (who owns each piece of memory)
  • [ ] One place Rust is used in the real world
  • [ ] One thing Rust is not good for

Next: Installing Rust.