A real Rust compiler,
in your pocket.

What it actually does

Four things that normally require a laptop, done on a phone.

The curriculum

Six language courses with 154 lessons, plus 20 independent solution-method chapters with 200 patterns and 600 steps ordered inside their method.

Rust FoundationsTypes, operators, functions, control flow, docs Ownership & BorrowingMoves, borrows, slices, Copy, Drop, lifetimes Modeling DataStructs, enums, Option/Result, strings, patterns AbstractionsGenerics, traits, closures, iterators, operators Real ProjectsModules, tests, errors, dependencies, workspaces Smart PointersBox, Rc, RefCell, Deref, Drop, cycles Fearless ConcurrencyThreads, channels, Mutex, Send & Sync Async RustFutures, runtimes, join and cancellation Macrosmacro_rules!, proc macros, cfg and features Systems Rustunsafe, FFI, performance, idioms Algorithm Atlas20 independent methods, 200 patterns, HOW → WHEN → Rust challenge Rust Interview PrepLanguage questions, systems design and live coding

Plus Quick Practice, Term Train with a timed mode, Code Recall, 37 achievement ladders of five tiers each, and a rating you earn across everything you do.

From the Crabrix blog

Notes about the local compiler and learning Rust with real projects.

Price

Buy it once. It is yours, on iPhone and iPad, with every update included.

The compiler and package manager ship in the app. All seven courses are included in the purchase; a new install lets you choose which ones to download for offline use. Existing learners keep their migrated offline material. Course downloads do not add a second transaction.

What it does not do

A compiler on a phone has real edges. Better you read them here than discover them later.

• Procedural macros do not run. They need a host-native compiler, so serde's derive feature and anything like it is reported as unsupported rather than silently mis-built.
• Bounded std-only WASI build scripts run locally. Scripts requiring host subprocesses, native linking or separate build-dependency graphs remain unsupported. Compatibility depends on the selected versions and features.
• Crates that link native C libraries are out of reach, as are ones that build only as cdylib or staticlib.
• Cold builds take time. rustc runs in an interpreter. Cached identical runs avoid recompiling; actual timings depend on the project, dependencies, device, and cache state.
• The codegen backend has gaps. Some crates hit unimplemented integer operations. Crabrix records the real outcome of every dependency build and shows it, with the compiler's own reason.

Questions

About

Crabrix is built by Serhii Ziborov. It began as one stubborn question — whether a real Rust compiler could type-check and run code inside an iPhone app while offline — and turned into a workspace once the answer was yes.

The source is publicly readable on GitHub for review and evaluation. It is commercial software, not an open-source project: reuse, redistribution, or derivative works need written permission. Bundled third-party components keep their own licences and attributions.