Senior Backend Engineer

A leading engineering team is investing in a centralized experimentation platform that powers A/B testing across web and mobile applications. This platform enables teams to design, launch, and analyze experiments that improve customer experience and drive business outcomes. Seeking a Senior Backend Engineer to design and scale backend services supporting real-time experimentation, high-throughput traffic, and data-driven decisioning. What You’ll Do Design and build scalable backend services using Node.js and TypeScript Develop APIs supporting the full experiment lifecycle (create, configure, launch, monitor) Build services for real-time variant assignment and experiment decisioning Design systems supporting server-side experimentation (including advanced models like multi-armed bandits) Build and optimize high-throughput, low-latency systems Integrate with analytics, clickstream, and monitoring platforms Design data flows for experiment tracking, metrics computation, and reporting Partner with data engineering and data science teams to ensure accurate measurement Contribute to a scalable, decoupled platform architecture Collaborate with product, UX, and cross-functional engineering teams Must-Have Qualifications 5+ years of backend software engineering experience Strong proficiency in Node.js (JavaScript/TypeScript) Experience building RESTful APIs and distributed services Experience with backend frameworks (Express, Koa, or similar) Strong understanding of scalability, performance optimization, and system design Experience with cloud-native architecture (Kubernetes, GCP, or similar) Experience with databases and data modeling (NoSQL, e.g., MongoDB) Nice to Have Experience with A/B testing, experimentation platforms, or feature flagging Experience with variant assignment or rollout systems Familiarity with event-driven or streaming architectures Exposure to analytics pipelines or experimentation metrics Experience in multi-language environments (Node, Go, Python) Background in eCommerce or customer experience optimization What Success Looks Like Scalable backend services supporting enterprise experimentation workflows Reliable real-time decisioning systems operating at scale High-performance systems handling large user volumes and traffic Accurate and scalable experiment tracking and analytics pipelines Continued evolution toward a centralized, decoupled experimentation platform Show more Show less