Staff MaaS Backend Engineer

You will co-own the architecture and implementation of a globally distributed Model-as-a-Service platform. You will develop Go services and compatible APIs, optimize model serving performance, manage Kubernetes-based deployments, enforce multi-tenant security, build accurate token metering and billing, execute safe migrations, and own reliability, observability, SLOs, and on-call operations.

Responsibilities

• Co-own the end-to-end MaaS system design and document technical decisions.
• Set Go and API standards and mentor engineers.
• Own OpenAI and Anthropic API compatibility including streaming tool calling and structured output.
• Develop intelligent routing with circuit breaking fallback and versioned APIs.
• Optimize token throughput KV caching and time-to-first-token latency.
• Integrate model deployment tooling LoRA multiplexing and autoscaling with Kubernetes.
• Scale regional inference pools and active-active control planes.
• Define and defend service level objectives and run load tests.
• Implement fail-closed authorization multi-tenant isolation rate limits quotas and abuse controls.
• Manage API keys and OAuth credentials.
• Build exactly-once token metering usage ledgers and billing reconciliation.
• Execute incremental migrations using shadow traffic and dual writes.
• Deliver request tracing cost telemetry and strict log hygiene.

Requirements

• 8+ years of backend engineering experience.
• 3+ years owning a high-traffic multi-tenant API platform for paying customers.
• Experience with multi-region active-active systems caching backpressure and performance engineering.
• Experience with zero-downtime migrations for stateful metering or ledger systems.
• Deep proficiency with Go-based services.
• Production Kubernetes experience including Envoy and GPU-aware scheduling.
• Experience with PostgreSQL Redis and Kafka.
• Experience with OpenTelemetry and high-cardinality analytics stores.
• Understanding of LLM serving including server-sent events KV caching and throughput optimization.
• Experience building exactly-once metering and billing systems.
• Experience designing fail-closed authorization and cross-tenant isolation.
• Experience with on-call operations and incident reviews.