Senior Engineer · SmartRouter & Inference Cost

Role overview

Build the routing and cost-management systems that decide which model should handle each request. The role sits at the intersection of backend engineering, machine-learning systems, inference economics, and evaluation: the goal is to meet quality and safety requirements while selecting the most efficient model and making the resulting trade-offs visible. The position is based in London or available remotely.

Responsibilities

- Implement request classification and routing across smaller, mid-tier, and frontier model options. - Integrate multiple model providers and account for differences in capabilities, latency, pricing, and operational behavior. - Measure inference cost end to end and expose current usage and savings through real-time FinOps dashboards. - Optimise the cost-versus-quality frontier using evaluation datasets, guardrails, and production performance data. - Design routing decisions and supporting telemetry so outcomes can be explained, reviewed, and audited. - Own improvements against customer-facing efficiency measures, including demonstrable reductions in model spend where quality remains acceptable.

Requirements

- Experience in backend engineering, ML systems, or platform engineering with a strong focus on cost and performance. - Practical knowledge of model serving, inference workflows, evaluation, and multi-provider integrations. - Demonstrated ability to use data to optimise complex systems and make measurable trade-offs. - Familiarity with telemetry, cost attribution, dashboards, or FinOps practices for compute-intensive services. - Comfort owning a system whose success is assessed directly through reliability, quality, and customer savings. - Clear thinking about explainability, controls, and auditability in automated routing decisions.

Benefits and work setup

- Senior full-time role with London or remote working options. - Remote-friendly arrangements across the UK, EU, and selected global time zones. - Equity participation and cash compensation benchmarked to leading London and remote markets.