Quotio is a macOS application for managing AI provider accounts and tracking quota usage. It follows a Clean Architecture with four layers: Domain (core models), Application (business logic), Infrastructure (platform services), and Presentation (SwiftUI UI). The app provides both Local Proxy Mode (running a local proxy server CLIProxyAPI) and Monitor Mode (quota-only tracking) for AI services like Claude, OpenAI Codex, GitHub Copilot, Antigravity, and others. Key features include OAuth authentication flows, secure credential storage (Keychain/YubiKey), menu bar integration, automatic updates via Sparkle, telemetry via PostHog, AI CLI tool configuration, and Cloudflare tunnel management. The application uses modern Swift concurrency, protocol-oriented programming, and actor-based state management.