Software Engineer, Knowledge Engine - Query Engine

About the role

Exa is an applied AI lab building a search engine that crawls the web, trains embedding models and runs high-performance vector databases. Its Knowledge Platform team builds a knowledge engine that turns information from across the web into a large open-domain knowledge graph. In this role you will own the query engine that searches hundreds of billions of claims across retrieval backends such as a distributed graph database, vector, full-text, time-series and geospatial indexes. It is greenfield work with a massive scope.

Key responsibilities

• Own storage and indexing across backends: data layout, partitioning and indexes for graph, vector, full-text, time-series and geospatial retrieval, with bulk snapshot builds and live ingest that never take the system down.
• Decide how best to search: cost-based planning using cardinality estimates to choose which backends to use, in what order and how to join their results, executed as traversals, retrievals, filters and aggregations in one plan.
• Make it fast at scale: serve thousands of queries per second, profiling and reducing p50/p99 latency, memory and cost per query under high concurrent load.
• Keep answers consistent while the data converges: consistent snapshot promotion, ordered application of live updates and stable pagination across versions.
• Measure precision and completeness: end-to-end checks for every deployment, plus evals and metrics that catch plans that return wrong results or miss ones they should have found.

Required profile

• Experience deep inside a distributed database, query engine, search engine or storage system.
• Solid grasp of distributed systems fundamentals: consensus, replication, sharding and fault tolerance.
• Strong in a systems language (Go, Rust or C++) and able to profile before optimizing, having shipped measured latency wins in production.
• Obsessed over correctness, reliability and data quality as much as scale.

Required skills

• Indexing, query planning and optimization, and storage formats.
• Bonus: graph databases, compilers, query language design or cost-based optimizers.

What we offer

• In-person position in Zurich; visa sponsorship available for international candidates (STEM OPT, OPT, H1B, O1, E3).
• Premium healthcare benefits (medical, dental, vision), fertility benefits.
• 16 weeks of fully paid parental leave for all new parents.
• Monthly wellness stipend for all employees.