Anvil
Offline-first desktop app for coding-interview and DSA practice. A guided course of 8 stages, 19 units and 62 lessons with animated diagrams and pattern drills, then real problems run in a sandboxed local runtime and judged against 3,000+ oracle-verified test packs. No account, no network, no AI crutch.
- Rust
- Tauri 2
- Next.js
- React
- TypeScript
- SQLite
- CodeMirror
The problem
Interview-prep sites hand you a wall of random problems and an AI helper that does the thinking, so the pattern recognition an in-person interview tests never gets built.
What was built
- A mastery-gated course: each lesson teaches one sub-pattern with trigger signals, an interactive prediction diagram, a worked example and faded practice.
- Unlabeled pattern-picker drills, and mastery gates of unseen problems solved hint-free under a soft timer before the next unit unlocks.
- A Rust sandbox that runs Python and JavaScript in an isolated subprocess with a timeout, a memory cap and temp-dir isolation (Job Objects on Windows); user code never runs in the WebView.
- Judging with no hand-typed answer keys: expected outputs come from reference solutions cross-checked in Python, JavaScript and a brute-force oracle, so a wrong solution cannot pass.
- FSRS spaced review on the device, a graduated hint ladder and deterministic complexity feedback from operation counts.
- Installers for Windows, macOS (Apple Silicon and Intel) and Linux, released from signed tags; MIT-licensed.