Senior Backend Engineer - Search Features & APIs (SABR)

Constructor

1d • Remote

About The Position

Constructor is an AI-first e-commerce search and discovery platform. The SABR team owns the top layer of product-discovery request processing, including the service that receives autocomplete, search, browse, and recommendation requests and coordinates the business logic behind discovery. The service acts as a gateway: it parses requests, orchestrates calls to internal ranking and retrieval services, interprets their responses, and assembles customer-facing results. The team also owns public configuration APIs and an MCP layer for AI agents.

The role combines platform and product engineering. The team's public APIs require thoughtful interface design and backward compatibility, while its services must remain fast and available at up to 15,000 requests per second, gracefully handling internal service failures and slowdowns. Work includes request orchestration, failure isolation, caching, latency budgets, capacity planning, and production observability. Engineers own problems end to end, from design through on-call.

The successful candidate will own feature and component design and delivery, evolve APIs and service architecture, improve performance and reliability, collaborate with product and engineering partners, review designs and code, mentor mid-level engineers, and participate in on-call and incident response.

Requirements

• Solid experience building and operating backend services in production, ideally high-traffic or low-latency services.
• Extensive knowledge of Python, the team's primary language.
• Hands-on experience with metrics, logs, and traces, and with debugging performance issues in live systems.
• Experience designing and evolving public APIs relied upon by external customers.
• Experience designing and implementing scalable service-oriented architectures.
• Track record of delivering projects end to end, including leading small efforts with other engineers.
• Collaborative approach, openness to feedback, and willingness to change position when presented with a better argument.
• Clear written communication, including design documents, RFCs, and postmortems.
• Good judgment about trade-offs and scope.
• Comfort working with ambiguity and loosely defined problems.
• Ownership that extends beyond code merge to how systems behave in production.
• Experience taking part in on-call for production services.

Nice To Haves

• Experience with AWS.
• Background in search, ranking, information retrieval, or e-commerce product discovery.
• Exposure to AI/LLM-facing infrastructure, such as MCP or agent tooling.

Responsibilities

• Own the design and delivery of features and components in the team's services.
• Design and evolve public API endpoints while maintaining backward compatibility, and contribute to service architecture discussions.
• Improve performance and reliability by identifying latency and failure hotspots, adding observability, and resolving issues.
• Participate actively in design and code reviews, and mentor mid-level engineers.
• Work with product, solutions/support, and other engineering teams to understand customer needs and develop technical solutions.
• Take part in on-call for owned systems, lead incident response, and follow through after incidents.
• Lead projects from initial problem definition and design through delivery and production operation.

Benefits

• Unlimited vacation time; employees are strongly encouraged to take at least three weeks per year.
• Fully remote team; employees can choose where they live.
• Work-from-home stipend for setting up a home office.
• Apple laptops provided for new employees.
• Annual training and development budget, refreshed each year.
• Maternity and paternity leave for qualified employees.
• Regular team offsites.
• Stock options offered in addition to base salary.

What This Job Offers

• Job Type: Full-time
• Career Level: Senior
• Education Level: No Education Listed