Nginx Proxy Manager is a full-stack web application that provides a graphical user interface and REST API for managing Nginx reverse proxy configurations, SSL/TLS certificates (via Let's Encrypt or custom uploads), TCP/UDP streams, access control lists, and user permissions. The system is designed to run as a Docker container and is primarily used by self-hosting enthusiasts and small-to-medium deployments to simplify the otherwise complex task of configuring Nginx and maintaining certificates. The architecture is a classic three-tier web application: a Node.js/Express backend (ES modules) with Objection.js/Knex ORM supporting SQLite, MySQL, and PostgreSQL; a React 18/19 frontend built with TypeScript, Vite, TanStack Query, and Tabler UI; and a set of s6-overlay managed services (backend, frontend, Nginx) inside a single Docker image. The backend generates Nginx configuration files from Liquid templates and reloads Nginx on any change. External dependencies include Nginx, Certbot (for Let's Encrypt), OpenSSL, and optionally a database server. Key entry points are `backend/index.js` (server startup, migration, setup, Express app) and `frontend/src/main.tsx` (React bootstrap). The primary data flow is: user creates or modifies a proxy host, redirection, stream, or certificate via the UI → API call → backend validates permissions and data → persists to database → regenerates relevant Nginx config files → tests configuration → reloads Nginx. The system also periodically checks for certificate expiration and renews via Certbot, and fetches IP ranges from Cloudflare/Cloudfront for access control. The codebase demonstrates solid engineering practices: a consistent internal service layer with access control and audit logging, a well-typed API client with automatic camelCase/decamelize conversion, a reusable table framework built on TanStack Table, and a comprehensive i18n system supporting 24+ locales. While some modules (e.g., certificate management) are large and could benefit from refactoring, the overall structure is clean and maintainable.