Software Engineer (Scala + ML Systems)

JOB DESCRIPTION

About The Team

• We own the single entry point for ML at Etsy. Our design decisions affect every team that ships a model.
• We treat the platform as a product. Our users are Applied Scientists and Software Engineers, and our goal is to make going from experiment to production safe, fast, and self-service.
• We work closely with Applied Scientists, Data Enablement, model serving and LLM hosting teams, and product engineering partners across Etsy.
• We use generative AI and other productivity tools thoughtfully, with a focus on learning and intentional contribution.

About The Role

We’re looking for a Senior Software Engineer to help build and run Etsy’s ML orchestration platform. Every ML request at Etsy goes through it, including search, recommendations, ads, trust and safety, and generative AI use cases. The platform handles online inference and model evaluation, and it connects product teams to the models, features, and serving infrastructure behind them. This is a high-scale, latency-sensitive, high-availability system, and its reliability directly affects the buyer and seller experience. 

Requirements

• 5+ years of software engineering experience building and operating distributed, low-latency production services.
• Experience with Scala or another functional programming language and comfort with functional patterns such as immutability, composition, and effect or concurrency libraries.
• A solid understanding of how ML inference works in production: model serving, feature retrieval, batching, latency and throughput trade-offs, and how predictive and transformer-based models are deployed and evaluated.
• Hands-on experience operating services on Kubernetes, including deployments, scaling, resource management, and debugging in production.
• Experience designing service APIs and request-routing or orchestration systems (e.g., gRPC, queues).
• Strong operational skills: metrics, tracing, alerting, on-call ownership, and performance profiling.
• A product mindset and strong communication skills. You enjoy working with internal users to understand their needs.

Must-Haves

• Back-end engineering experience working on ML systems
  Knowledge of how ML works
  Scala language expertise
  
  

Nice-to-Haves

• • Experience with cloud infrastructure, ideally GCP.
  • Experience with model serving frameworks and LLM inference infrastructure (e.g., vLLM, Triton, KServe).
  • Experience with experimentation platforms, feature stores, or online evaluation systems.
  • Experience with GPU capacity management and cost optimization.
  • Experience with Scala libraries and frameworks such as Cats Effect, ZIO, Akka/Pekko, or http4s.