We are seeking a Staff Backend Engineer to take our Model-as-a-Service (MaaS) working system and re-architect it into a commercial, globally distributed, multi-tenant token service — one that sustains at least millions of monthly active users, high sustained token throughput per GPU, and invoice-grade accounting, with scalability, reliability, and observability engineered in deliberately rather than absorbed under load. Global Topology and Reliability (SLOs): Scale the platform to a globally distributed architecture featuring regional inference pools, capacity-aware failovers, and an active-active control plane.