# API Reference

The API reference provides detailed descriptions of SimPy’s classes and functions. It should be helpful if you plan to extend SimPy with custom components.

- `simpy`
- `simpy.core` — SimPy’s core components
- `simpy.exceptions` — Exception types used by SimPy
- `simpy.events` — Core event types
- `simpy.resources` — Shared resource primitives
- `simpy.rt` — Real-time simulation
- `simpy.util` — Utility functions for SimPy