Part 7 of the POE2 Overlord series. Covers the testing strategy across both Rust and TypeScript: frontend testing with Vitest, React Testing Library, and jsdom including global Tauri API mocking, co-located spec files, mock data factories with type-safe overrides, and semantic DOM queries; backend testing with native Rust tests, async service tests with trait-based mocking, concurrency validation, and time calculation edge cases; plus an honest look at what 100% component coverage catches and where it falls short.

Part 6 of the POE2 Overlord series. A full-stack deep dive into two features: the economy integration (fetching live currency data from poe.ninja with cache-first stale fallback, concurrent request deduplication via per-key semaphores, and league-specific data handling) and the campaign walkthrough system (a 2800-line guide data structure, per-character progress tracking, automatic step advancement from zone changes, and reactive frontend rendering with event-driven updates).

Part 5 of the POE2 Overlord series. Covers the React 19 frontend architecture: file-based routing with TanStack Router, server state management with React Query and tuned stale times, the 6-provider dependency graph, centralized query hook patterns, domain-grouped component organization with co-located tests, custom filter/sort hooks, data visualization with Recharts, and Tailwind v4 styling.

Part 4 of the POE2 Overlord series. Covers the event-driven communication layer between the Rust backend and React frontend: the in-memory pub/sub event bus, the Tauri event bridge that forwards domain events to the webview, the useAppEventListener hook, the full data flow from log parse to UI re-render, Tauri commands for frontend-to-backend calls, type safety across the Rust/TypeScript boundary with Serde, and pitfalls like stale closures and event ordering.

Part 3 of the POE2 Overlord series. Covers the real-time log analysis pipeline: how the app watches Client.txt via polling, parses log lines through a modular parser pipeline with regex pattern matching, detects session gaps, and cascades a single zone change event across four domains to update character location, walkthrough progress, zone statistics, and the frontend.

Part 2 of the POE2 Overlord series. Walks through the Rust backend architecture: domain file structure, async traits with dependency injection via Arc<T>, the service registry that boots 10 services in dependency order, unified error handling with thiserror, Tauri commands as the IPC bridge, and file-based JSON persistence with atomic writes.

Part 1 of a series on building POE2 Overlord, a desktop companion app for Path of Exile 2. Covers why I built it, the decision to go with Tauri over Electron, the monorepo structure, domain-driven design with 10 bounded domains, and how the Rust backend and React frontend fit together.