Senior Search Backend Engineer (m/f/x)

About This Role

We are representing a confidential SaaS client seeking a Senior Search Backend Engineer to join their Discovery team in London. This is a hybrid position requiring three days per week in the London office.

Our client is building the next generation of product search and discovery infrastructure at enterprise scale. As search evolves from keyword matching to semantic understanding—where shoppers type full sentences and AI agents call APIs—you'll tackle the hard engineering problems that make hybrid retrieval fast, cost-effective, and measurably better across massive catalogs.

Responsibilities

• Design and implement search functionalities in a Scala-based backend platform
• Develop search capabilities combining lexical, semantic, and hybrid retrieval approaches
• Build and maintain search libraries based on ElasticSearch and MongoDB
• Contribute to search relevance, quality measurement, and ranking optimization
• Run and maintain scalable search infrastructure as code on Kubernetes using Terraform in a multi-tenant architecture
• Test software components for usability, functionality, and performance
• Collaborate closely with Product Management and DevOps teams
• Learn Scala and functional programming patterns as primary development tools
• Participate in on-call rotation with a globally distributed team for production systems

What We're Looking For

Required qualifications:

• At least 5 years of experience as a Software Engineer with production JVM experience
• Solid understanding of parallel and asynchronous programming, plus non-blocking I/O
• Experience developing REST APIs and knowledge of scalable architectures including sharding, replication, load balancing, and failover
• Interest in working with Scala using pragmatic functional programming patterns (support provided if transitioning from another JVM language)
• Fluent English for international team collaboration
• Experience operating multi-tenant SaaS where tenant isolation is critical
• Knowledge of scalable event-driven architectures including queues and notification topics
• Genuine curiosity for using AI tools to work more effectively

Preferred qualifications:

• Hands-on search experience with ElasticSearch or OpenSearch, including understanding of inverted index scoring and ranking
• Practical exposure to vector retrieval, embeddings, approximate nearest neighbor indexes, and hybrid ranking—or deep lexical search background with appetite to expand into this territory
• Ability to reason about relevance using data, including precision/recall tradeoffs, ranking metrics, and behavioral signals
• Experience with infrastructure technologies such as Helm, Kubernetes, and Rust

How We Work With You

When you apply through Get A Job.ai, our talent team will review your background and schedule an initial screening call. We'll discuss your experience, career goals, and the role requirements in detail. If there's a strong match, we'll submit your profile to our client and guide you through their interview process.

Please apply exclusively through Get A Job.ai—do not contact the client directly, as this may disqualify your application.

Pay

Compensation details will be discussed during the screening process based on your experience level and the client's budget for this position.

Equal Employment Opportunity: Get A Job.ai is committed to creating an inclusive recruitment process. We welcome applicants of all backgrounds and provide equal opportunity regardless of race, color, religion, gender identity, sexual orientation, age, disability status, or any other characteristic protected by law.