Systems Design Case Study
AI Cost & Usage Control System
Designing a cost-aware control layer that treats AI usage like infrastructure, not an unlimited resource.
The Problem
AI costs scale faster than usage expectations. Without guardrails, teams lose visibility, predictability, and budget control.
Constraints
- • Multiple models with different pricing
- • Per-user and per-feature budgets
- • Minimal latency overhead
- • Clear visibility into spend
Key Decisions
- • Enforce budgets before model execution
- • Track tokens as billable units
- • Route requests dynamically by cost targets
- • Expose usage as first-class metrics
Outcome
- • Predictable AI spend
- • Clear cost attribution
- • Safer experimentation