# Introduction
# Advanced concepts in HELICS
- Values vs. Messages
- What are Filters and why should I care?
- Call-backs
- HELICS Flags
- Co-iteration
- Asynchonous process
- HELICS CLI and future orchestration directions
- Multi-node, multi-broker, and heterogenous computing environments
- Different backend options and ones you might need.
- C++ API
- Roadmap