Senior Backend Engineer - Search Features & APIs (SABR)

Constructor; San Francisco (CA); Remote; USD 80,000 - 120,000; Full time

Benefits offered by this job

Unlimited vacation

Remote work

Work from home stipend

Apple laptops provided

Training budget

Parental leave

Stock options

Team offsites

Job summary

Constructor is seeking a senior backend engineer to own features end to end, from design to production. You will run production Python services, focus on latency-sensitive workloads, and participate in on-call responsibilities to ensure reliability.

You will design and evolve public APIs with backward compatibility, improve performance, and mentor junior engineers while collaborating with product and other teams.

Qualifications

• Solid experience building and operating backend services in production, ideally high-traffic or low-latency.
• Extensive Python knowledge (primary language).
• Hands-on 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 scalable service-oriented architectures.

Responsibilities

• 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.

Skills

Python

Backend design & ops

Observability

Public API design

SOA design

End-to-end ownership

Team leadership

Technical communication

Trade-off judgment

Production on-call

Tools

AWS

Job description

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 scalable service-oriented architectures.

Beyond the code

• Track record of delivering projects end to end, including leading small efforts with other engineers.

• Collaborative mindset: open to feedback, and willing to change your position when someone has a better argument.

• Clear written communication - design docs, RFCs, postmortems.

• Good judgment about trade-offs and scope.

• Comfort with ambiguity and loosely defined problems.

• Ownership that extends past merge, to how the system behaves in production.

Nice to have

• Experience with AWS

• Background in search, ranking, information retrieval, or e-commerce product discovery.

• Exposure to AI/LLM-facing infrastructure (MCP, agent tooling, or similar).

Benefits

Unlimited vacation time - we strongly encourage all of our employees take at least 3 weeks per year

Fully remote team - choose where you live

Work from home stipend! We want you to have the resources you need to set up your home office

Apple laptops provided for new employees

Training and development budget for every employee, refreshed each year

Maternity & Paternity leave for qualified employees

Work with smart people who will help you grow and make a meaningful impact

Base salary: $80k–$120k USD, depending on knowledge, skills, experience, and interview results TBD

Stock options - offered in addition to the base salary

Regular team offsites to connect and collaborate

Diversity, Equity, and Inclusion at Constructor

At Constructor.io we are committed to cultivating a work environment that is diverse, equitable, and inclusive. As an equal opportunity employer, we welcome individuals of all backgrounds and provide equal opportunities to all applicants regardless of their education, diversity of opinion, race, color, religion, gender, gender expression, sexual orientation, national origin, genetics, disability, age, veteran status or affiliation in any other protected group.

Studies have shown that women and people of color may be less likely to apply for jobs unless they meet every one of the qualifications listed. Our primary interest is in finding the best candidate for the job. We encourage you to apply even if you don’t meet all of our listed qualifications.

How we handle your data. By submitting this application, you acknowledge that Constructor will collect and process the personal data you provide for the purpose of evaluating your candidacy for this role. If you are not selected, we will retain your data for a limited period as described in our Recruitment Privacy Notice. After that period your data will be deleted or anonymized.

How we handle your data. By submitting this application, you acknowledge that Constructor will collect and process the personal data you provide for the purpose of evaluating your candidacy for this role. If you are not selected, we will retain your data for a limited period as described in our Recruitment Privacy Notice. After that period your data will be deleted or anonymized.