AI applications depend on constrained services: model providers, embedding APIs, vector databases, browser tools, code execution sandboxes, and third-party business APIs. Each service may enforce request limits, token limits, concurrency limits, daily quota, spend tiers, or safety throttles. Without a control layer, traffic spikes become 429s, retries amplify the spike, and cost overruns look like product growth until the bill arrives.

In this chapter, we build an API management layer for AI workloads: rate limits, priority queues, budgets, upstream throttling, load shedding, and API key hygiene.