Anki is a mature, cross-platform spaced-repetition flashcard application. While it is fundamentally an end-user product, it contains significant embedded algorithmic and data-analysis components (FSRS memory-state scheduling, revlog analytics, retention simulation) that make it a hybrid of application and computational research. The production system consists of a Rust backend that owns all core logic, scheduling, SQLite persistence, sync, and media management; a Python Qt desktop frontend (`aqt`); a TypeScript/Svelte web UI for modern editors, graphs, deck options, and image occlusion; and a standalone sync server binary. Communication between languages is driven by protobuf service definitions, with generated bindings for Rust, Python, and TypeScript.
TypeWords is a browser-based English vocabulary and article memorization application built with Nuxt 3 / Vue 3. It operates on a local-first architecture, storing user progress in IndexedDB, with an optional (now obsolete) Supabase cloud sync. The application is a monolith SPA but is well-modularized into a custom UI kit (app/base/), core business logic (app/core/), and page components (app/pages/). The core learning mechanic is typing-based practice, supporting multiple modes (follow-write, dictation, self-test, spelling) for both individual words and full articles. It integrates the FSRS (Free Spaced Repetition System) algorithm for intelligent review scheduling. Static dictionary data (CET-4, GRE, NCE articles) is loaded from bundled JSON files. The practice flow is managed by a sophisticated, serializable state machine (practice-flow-types/runtime), demonstrating strong architectural patterns. The codebase exhibits high craftsmanship in several isolated components, such as the global dialog stack, event bus, and versioned cache. These are genuinely reusable patterns. However, the project suffers from significant technical drift: it relies on experimental Vue Macros ($ref/$computed), has zero automated tests, contains dead code (obsolete Supabase sync), and bundles third-party libraries statically. The TypeScript configuration is lax (strict: false), increasing refactoring risk. TypeWords is a feature-rich, community-driven project (10k+ stars) that effectively solves a specific learning problem. Its architecture is a valuable study for developers building local-first, content-rich Vue applications. However, its lack of tests and reliance on experimental features make it a risky candidate for direct production reuse without significant hardening. It is best suited for educational analysis or as a foundation for a new project willing to address the technical debt.