Senior Backend Engineer - Search Features & APIs (SABR)

About us Launched in 2019, Constructor is an AI-first e-commerce search and discovery platform that helps shoppers find the right products at the right time and enables leading global e-commerce brands to drive meaningful revenue and conversion gains. About the team The SABR team owns the top layer of request processing for product discovery. We own the service that first receives product discovery requests (autocomplete, search, browse & recommendations) & executes the entire business logic that drives product discovery. That service also functions as a gateway to parse incoming user requests, orchestrate calls across the internal services that do the ranking and retrieval, interpret their responses, and assemble the final response the customer sees. We also own the public configuration APIs customers use to control how discovery behaves, and the MCP layer that exposes all of it to AI agents. Our team owns both platform & product components: Because of the positioning of our services, we take part in every architectural decision of our core product offering. At the same time, our goals are heavily influenced by direct customer feedback, because all product discovery-related features are either implemented in or integrated with our services. All of our services are public APIs, so interface design and backward compatibility are a constant part of the job. But most of our attention goes to keeping them fast and up: we serve up to 15k RPS, fan out to many internal services on every request, and are expected to stay available and degrade gracefully when any of them fails or slows down. The work is distributed systems in practice rather than in theory: request orchestration, failure isolation, caching, latency budgets, capacity planning, and the observability to know what is actually happening in production. The team is small enough that engineers own problems end to end, from design through on-call. About you You're a senior engineer who wants to own features end to end, not just close tickets. You've built and run production Python services, ideally high-traffic or latency-sensitive ones, and you've been on-call for them. You think in trade-offs: latency versus cost, a quick fix versus a durable one, a new parameter versus a public API customers can't afford to see break. You can take a feature from a rough problem statement to a design, ship it, and then make sure it behaves in production. You're comfortable leading a project with one or two other engineers and helping teammates grow along the way. When a problem is only partly defined, you ask the right questions to pin it down. When you meet an unfamiliar protocol or system, you read the spec and work out how it fits. You change your mind when someone has a better argument, and you still care about your code long after it merges. What you will do Own the design and delivery of features and components in our services. Design and evolve public API endpoints with backward compatibility in mind, and contribute to architecture discussions for our services. Improve performance and reliability: find latency and failure hotspots, add the observability needed to understand them, and fix them. Take an active part in design and code review, and mentor mid-level engineers. Work with product, solutions/support, and other engineering teams to understand customer needs and turn them into solid technical solutions Take part in on-call for the systems you own, and lead incident response and follow-through when things break. What we are looking for Technical Solid experience building and operating backend services in production, ideally high-traffic or low-latency ones. Extensive Python knowledge (our primary language). Hands-on experience with observability (metrics, logs, traces) and debugging performance issues in live systems. Experience designing and evolving public APIs that external customers depend on. Experience designing & implementing