learn by writing real Rust

Get fluent in Rust,
one challenge a day.

Bite-size challenges compiled by a real rustc in the cloud. No setup, no tutorials to skim - just the borrow checker, a failing test, and you.

Learn by practice Playground

KMAJ

12,400 rustaceans practicing · 140 challenges · 1,200,000 submissions

ring_buffer.rs▸ cargo test

1 2 3 4 5 6 7 8

impl <T> Iterator for RingBuf<T> { type Item = T; fn next(&mut self) -> Option<T> { // yield oldest → newest, no alloc let item = self.buf[self.head]; Some(item) } }

4 passed0 failed · finished in 0.18s

the daily

Everyone solves the same puzzle today

A fresh, hand-picked challenge drops at midnight. Keep your streak, climb the daily board, and compare your solution with the rest of the cohort.

curriculum

5 tracks, first `println!` to async

Each track is an ordered run of challenges, so every new concept builds on the one you just earned. Start anywhere - we'll remember where you left off.

01track / beginner

Rust Fundamentals

Master the basics of Rust programming language, from syntax to ownership concepts.

76 challenges~12.1hbeginner

ownershipsyntaxstdlib

start freshstart

02track / beginner

Control Flow

Learn how to control the flow of your Rust program using loops and conditional statements.

15 challenges~2.8hbeginner

start freshstart

03track / intermediate

Rust Standard Library

Explore the Rust Standard Library and learn how to use its powerful features.

55 challenges~9.7hintermediate

start freshstart

04track / intermediate

locked

Mastering Option<T>

Learn how to use the Option<T> type to handle optional values in Rust.

0 challenges~0mintermediate

optionpatterns

coming soonlocked

05track / intermediate

locked

Mastering Result<T, E>

Learn how to use the Result<T, E> type to handle errors in Rust.

0 challenges~0mintermediate

resulterrors

coming soonlocked

how it works

Built on the real Rust toolchain

01

Real rustc, not a sandbox

Your code is compiled by the actual Rust toolchain in the cloud. The errors you see are the errors you'll fight in production - E0502 and all.

02

Tests, not vibes

Every challenge ships a hidden test suite. You're done when it's green - no guessing whether your Iterator actually yields the right order.

03

Streaks that compound

Show up daily and keep the flame going. A few minutes a day adds up, and the borrow checker gets less intimidating with every rep.

Your first challenge is already waiting.

A new challenge every day. No setup, no cargo install - open the editor and write a line of Rust.

Start today's challenge Explore the curriculum