We're seeking a high-performance API engineer who thrives on the challenge of building systems that need to respond in single-digit milliseconds at scale. You'll be responsible for building and maintaining our feature flags evaluation engine that makes complex decisions based on person/group properties at high speed and scale. You'll be making high-level architecture decisions, optimizing a performance bottleneck that slashes latency by 50%, and working directly with customers to implement complex targeting rules that meet their specific needs.