Senior Backend Engineer

This team is investing in its centralized experimentation platform which powers A/B testing across web and native applications. This platform enables teams to design, launch, and analyze experiments that improve customer experience and business outcomes. This role focuses on building and scaling backend services and APIs that support experiment configuration, variant assignment, analytics, and reporting. You will work on systems that enable real-time decisioning, handle high-throughput traffic, and integrate with analytics and data platforms at enterprise scale.

We are seeking a Senior Backend Engineer (Node.js) to design and build distributed systems powering experimentation workflows and real-time experimentation services.

• Design and build scalable Node.js / Type Script services supporting experimentation workflows
• Develop APIs for experiment lifecycle management (create, configure, launch, monitor)
• Build services for variant assignment and real-time decisioning
• Support server-side experimentation and advanced testing models (e.g., multi-armed bandits)
• Build systems handling large-scale traffic and real-time experiment evaluation
• Optimize services for low latency, high availability, and resilience
• Integrate with clickstream, analytics, and monitoring platforms
• Design data flows for experiment tracking, metrics computation, and reporting
• Partner with data engineering and data science teams to ensure accurate experiment measurement
• Contribute to evolving the platform toward a decoupled, scalable architecture
• Help build new services such as centralized variant assignment systems
• Collaborate cross-functionally with product, UX, and engineering teams

• 5+ years of backend software engineering experience
• Experience building RESTful APIs and distributed services
• Experience with backend frameworks (Express, Koa, or similar)
• Strong understanding of distributed systems, scalability, and performance optimization
• Experience with cloud-native architectures (Kubernetes, GCP, or similar)
• Experience with databases and data modeling (No
  
  SQL such as Mongo
  
  DB)

• Experience designing systems for high throughput and low latency
• Strong understanding of scalability, resilience, and performance optimization
• Ability to support real-time decisioning systems

• Experience building and maintaining RESTful APIs
• Integration with analytics, monitoring, and data platforms
• Ability to design systems that support experiment configuration and execution workflows
• Experience with data modeling and No
  
  SQL databases (e.g., Mongo
  
  DB)
• Familiarity with experiment tracking, metrics computation, and reporting pipelines
• Ability to design data flows for analytics and experimentation platforms

• Experience with A/B testing, feature flagging, or experimentation platforms
• Experience implementing variant assignment or feature rollout systems
• Familiarity with event-driven architectures and streaming pipelines
• Exposure to analytics pipelines or experimentation metrics
• Experience working in multi-language environments (Node, Go, Python)
• Knowledge of eCommerce platforms and customer experience optimization

• Scalable backend services supporting enterprise experimentation workflows
• Reliable systems enabling real-time experiment decisioning at scale
• High-performance services handling millions of users and high traffic volumes
• Accurate and scalable experiment tracking and analytics pipelines
• Continued evolution toward a decoupled, centralized experimentation platform