Expert Backend Engineer (Vespa Search Engine) - SRA Team, Singapore

As part of the Search, Recommendation, Ads (Engineering & Architecture) team, we build and operate the search engine that powers retrieval and ranking across the company. The system is built on Vespa (a ~1.7M-line C++/Java codebase) and runs at scale across hundreds of nodes. Our work spans the full stack: cluster orchestration, HNSW-based vector indexing, rank expression evaluation, capacity planning, and the developer tooling that keeps all of it shippable. We care a lot about correctness, latency tails, and operational simplicity.

• Design, implement, and operate components of the search engine — indexing, query execution, ranking, or storage using C++
• Improve indexing and retrieval performance: SIMD‑friendly data layouts, cache‑aware algorithms, lock contention
• Extend vector search capabilities (HNSW and beyond) and integrate them cleanly with traditional inverted‑index retrieval
• Build tooling and automation that makes the team faster — capacity models, fault‑injection tests, deployment checks, AI‑assisted workflows
• Participate in design reviews, code reviews, and on‑call rotation

• Bachelor’s Degree or higher in Computer Science
• At least 5 years of full time backend development experience using C++
• Experience working on a search engine, database, or storage system such as Vespa is preferred
• Familiarity with vector search and ANN algorithms (HNSW, IVF, PQ)
• Solid foundation in data structures, algorithms, and systems. You can reason about cache behavior, memory layout, and concurrency.
• Experience operating non‑trivial services in production: profiling, debugging core dumps, reading flamegraphs, tracing distributed requests.
• Comfortable working in a large existing codebase
• Strong written communication. You write design docs and PR descriptions that the next on‑call can actually use.