Online compiler, debugger and visualizer

Online Rust compiler

Compile and run Rust 1.90 online with rustc (2021 edition). The compiler's errors link to the exact line and column, a panic stops in the debugger where it happened, and you can step through the program with breakpoints or watch it run in the visualizer: Vec, HashMap, structs and Option<Box<..>> lists drawn as they change.

Open the Rust compiler
  • Free
  • No sign-up
  • Real compilers
  • Works on phones
main.rs
use std::io; fn main() {    let mut line = String::new();    io::stdin().read_line(&mut line).unwrap();    let n: u64 = line.trim().parse().unwrap();    let squares: Vec<u64> = (1..=n).map(|x| x * x).collect();    println!("{:?}", squares);}

What you can do

  • Real Rust 1.90

    Your code is compiled and run by the real Rust toolchain on our servers, not a simulation, with the exact errors you would see on your own computer.

  • Input while it runs

    Programs that read input (Scanner, input(), scanf, cin) ask for it in the console as they run, just like a terminal. Or prepare the input in advance.

  • Step-by-step debugger

    Set breakpoints, step over, into and out, and watch variables and expressions change, right in the browser.

  • Visualizer

    Replay your program line by line and see arrays, objects and the call stack drawn as it runs. Ideal for learning recursion and data structures.

  • Test cases

    Add inputs with the expected output and run them all with one click. See which lines differ, like on a coding judge, for any code you write.

  • Errors explained

    Compiler and runtime errors link to the exact line, with a plain-English explanation of what went wrong and how to fix it.

  • Help that sees your code

    Ask why a test fails or what an error means. The assistant sees your files and the real output, and can fix the right line for you.

  • Code together live

    Share a link and code with friends or students in real time: shared cursors, edits, runs and test results.

How it works

  1. 1

    Click "Open the Rust compiler". A project with a ready-to-run main.rs opens.

  2. 2

    Write your code. Files save automatically in your browser as you type.

  3. 3

    Press Run (Ctrl+Enter). If the program reads input, type it in the console, or press Debug (F5) to step through it.

  4. 4

    Add test cases to check your program against expected outputs, or share a live link to code with someone.

Open the Rust compiler

Questions and answers

Which Rust version and edition?

Rust 1.90, 2021 edition, with the standard library.

Can I split code into modules?

Yes. Add a file such as util.rs and declare it with `mod util;` in main.rs.

Can I use crates?

No. Programs run with no internet access, so only the standard library is available.

Is it free?

Yes. Running, debugging, tests and live sessions are free, with no sign-up.

Where are my projects saved?

In your browser, on your device, automatically as you type. Nothing is lost when you close the tab. They stay until you delete them.

Is my code safe to run?

Every program runs in its own isolated sandbox with no internet access and strict limits on time, memory and processes, and is deleted when it finishes.

Compilers and tools