Sopel is a mature, plugin-based IRC bot framework written in Python. It provides a full IRC protocol stack (including IRCv3 capabilities, SASL, ISUPPORT, mode parsing), a flexible plugin system with decorator-driven commands/rules/jobs, configuration management with validated types, persistent storage via SQLAlchemy (SQLite, PostgreSQL, etc.), and a CLI for daemon management (start/stop/restart/configure). The bot dispatches incoming IRC messages to registered plugins, handles channel/user state tracking, rate limiting, and flood protection. It ships with a rich set of built-in plugins (admin, dice, currency, translate, seen, tell, etc.) and supports external plugin packages via entry points. The architecture is a single-process event loop (with an asyncio backend) that loads plugins as Python modules, with a rule-based matching engine for message handling. External dependencies include SQLAlchemy, requests, pytz, and various API integrations. The codebase is well-tested with a custom pytest plugin and VCR cassettes for network-dependent tests.