Design a cost-control and quota system for an internal LLM platform serving many teams.
Hand every team an LLM API key and your bill turns into a mystery capped by a six-figure surprise at month end. Attributing, capping, and optimizing spend is a platform feature. Here is how to build it.
Updated Sep 2026 · Grounded in real GenAI, LLM, and AI/ML engineering interview loops and written to a senior-engineer editorial bar.
Hand every team an LLM API key and your bill turns into a mystery capped by a six-figure surprise at month end. Attributing, capping, and optimizing spend is a platform feature. Here is how to build it.
Lead with where the obvious approach breaks, because that is the judgment they are screening for — most candidates jump straight to the happy path and lose the room.
Then walk the failure back through the pipeline in order, naming the one metric the customer's exec sponsor actually cares about before you propose the fix.
