# Core Concepts

- [Architecture & Parallel Execution](/reference-material/core-concepts/architecture.md): Learn about the Substreams architecture
- [RPC Protocol](/reference-material/core-concepts/rpc-protocol.md): Substreams RPC protocol versions and performance optimizations
- [Foundational Stores](/reference-material/core-concepts/foundational-store-reference.md): Foundational Store architecture, components, and technical reference
- [Module Concepts](/reference-material/core-concepts/modules.md): Learn the basics about modules
- [Module Caching](/reference-material/core-concepts/module-caching.md): Learn how Substreams modules are cached for efficient execution
- [Reliability Guarantees](/reference-material/core-concepts/reliability-guarantees.md)
- [FAQ](/reference-material/core-concepts/faq.md): StreamingFast Substreams frequently asked questions