Llm Gateway Cost And Caching easy
Your gateway serves a feature where most requests are simple ticket classifications, but some need multi-step reasoning. You want to reduce cost without hurting quality. Which routing policy fits best?
- A Send all traffic to the cheapest available model, since each request then costs the least possible.
- B Default to a small model and escalate to a large one on failure or a classifier signal.
- C Send all traffic to the largest model so that no request ever needs to be retried.
- D Route requests randomly across models to spread the load evenly over providers.
Answer: B. Default to a small model and escalate to a large one on failure or a classifier signal.
Routing is a policy: a small model handles the easy majority cheaply, and escalation protects the **quality floor** on hard requests, at the cost of extra latency on escalated calls. Always using the cheapest model looks like a win, but failed answers and retries on hard requests erase the savings. Sending everything to the large model is only sensible when nearly all traffic is hard.
One system design question a day, with spaced repetition so the ones you miss come back.
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