Senior Backend Engineer (Node.js/TypeScript, OpenSearch)

We are looking for an experienced consultant to join our team as a backend specialist on Trade Insight — the API that serves static and market data for every financial instrument available in our new investment app, and soon across all of the bank's retail channels. Trade Insight is powered by OpenSearch, which we use not just as a data store, but as a highly optimized search and ranking engine. It's what lets us find, slice, sort and rank instruments and assets across any dimension needed to support good investment decisions — at high speed and low latency. Alongside the API itself, you'll work on the data ingestion pipeline that compiles and normalizes data from multiple external sources into it. The job is not just about delivering code, but customer value. Your primary task is always to understand what matters most to our customers and collaborate with the rest of the team to deliver that. You are also expected to use TDD as a way to design code and systems, whether the tests are unit tests or full e2e flows using test containers to replicate the live environment. Releases are done daily, so the build artifacts in CI must always be trusted to work. To thrive in this role, we believe you have Extensive, hands-on experience with and deep knowledge of OpenSearch or Elasticsearch — not just as storage, but as a search and ranking engine: indexing strategy, complex query design, aggregations, sorting/ranking across multiple dimensions, and performance tuning for low-latency workloads at scale. This is the core skill we're hiring for. Experience self-hosting and operating OpenSearch/Elasticsearch clusters is a strong bonus. Solid, hands-on experience with Node.js and TypeScript for building production APIs. Experience building data ingestion pipelines that combine and reconcile data from several external sources. A genuine interest in — and ideally experience with — financial instruments, markets, key figures, and financial analysis, since that's the domain Trade Insight serves. Experience working in an agile way, or willingness to learn.