Prompt Caching and Context Caching
Your system prompt is 4,000 tokens. Your RAG context is 20,000 tokens. You send both with every request. You also pay for both — every time. Prompt caching lets the provider keep that prefix warm on their side and bill you 10% of the normal rate on reuse. Used correctly, it cuts inference cost by 50–90% and first-token latency by 40–85%.
Visual edition planned
This lesson isn’t interactive yet.
It is part of the curriculum and will get the same treatment as Phase 1 — a visual cover, hands-on labs, derivations with numeric checks and a quiz. Until then, the original lesson is the best place to read it:
Part of Phase 11 — LLM Engineering. Use the previous / next cards below to keep browsing the phase.