PocketBase is an open-source backend-as-a-service (BaaS) platform written in Go. It provides a complete backend solution including a REST API, embedded SQLite database, authentication (password, OAuth2, OTP, MFA), file storage (local or S3), real-time subscriptions via SSE, cron jobs, email sending, and an admin dashboard UI. The architecture is a monolithic Go application with a plugin system (JavaScript VM, automigration, self-update) and a custom reactive JavaScript frontend for the admin panel. Key entry points are the CLI commands (`serve`, `superuser`) and the Go library package for embedding. The codebase is well-structured with clean separation of concerns: `core/` contains models and business logic, `apis/` handles HTTP endpoints, `tools/` provides reusable utilities (hook system, router, auth providers, search/filter, security, filesystem abstraction), and `ui/` is the frontend. It is production-ready with extensive test coverage and active maintenance.