Backend Engineer, Ranking & Personalization (Remote)

  • Anywhere

About Us

Constructor powers product search and discovery for some of the largest retailers in the world, like Sephora and Petco. We serve billions of requests every day, and you’ve probably seen our results somewhere and used our product without knowing it. We differentiate ourselves by focusing on metrics over features, and reinventing search and discovery from the ground up as a machine learning challenge with the specific goal of improving metrics like revenue. We have grown several hundred percent YoY for the last 2 years and have customers in every eCommerce vertical, around the world, and spanning many languages.

We’re a passionate team of technologists who love solving problems and want to make our customers’ and coworkers’ lives better. We value empathy, openness, curiosity, continuous improvement, and are excited by metrics that matter. We believe that empowering everyone in a company to do what they think is best can lead to great things.

About the Team

The Ranking & Personalization team, within Data Science and Engineering, plays a central role in implementing algorithms that optimize for business KPIs like revenue & conversions. We focus on metrics over features, arming our ranking algorithms with powerful capabilities that bring value to customers in the way they care the most about. 

The team is a cross-functional team, consisting of ML, BE, FE engineers and designers, owning & collaborating on multiple projects. As a member of the R&P team, you will be surrounded by and encouraged to use world-class analytical, engineering and machine learning techniques on big data to shape the evolution and scale our search algorithms. R&P team owns all stages of product ranking for Search, Browse and Autocomplete experiences, including base ranking, ML ranking, personalization, and ranking explanation.

One of the main services R&P owns is the ML Ranking Service which is a high load distributed REST service deployed in the cloud and developed in Python programming language. The service extensively uses in-memory and NoSQL DBs (for signals and model metadata storage). We support service deployment and stability. We have monitoring set up with Prometheus, PagerDuty, Sentry,  custom internal APIs with FastAPI). 

Challenges you will tackle

A primary focus of this job is to design, deliver & maintain highload real-time web services in close collaboration with other great engineers from the Ranking & Personalization team. The job can consist of, but is not limited to:

  • Build / deploy / support robust highload real-time (ML) system(s) for personalized search and browse experiences. 
  • Collaborate with technical and non-technical business partners to develop / update ranking functionalities
  • Optimize current ranking service performance to process requests faster
  • Optimize signals delivery and retrieval (aka Feature Store) for ML models inference
  • Communicate with stakeholders within and outside the team


Hard skills:

  • Experience in designing, developing & maintaining highload distributed real-time services (in cloud)
  • Proficiency in Infrastructure as Code (IaC) tools like CloudFormation or Terraform for managing cloud resources.
  • Hands-on experience with setting up and improving CI/CD pipelines
  • Proficiency with Python and, as a plus, compiled language like C, Rust, or Go.  
  • Experience in server-side coding for web services, and a good understanding of API design principles.
  • Skilled in setting up and managing observability tools like Prometheus, Grafana, and integrating alert systems like PagerDuty.
  • Familiarity with Service-Oriented Architecture, knowledge of communication protocols like protobuf & familiarity with networking principles
  • Experience with NoSQL and relational databases, distributed systems, and caching solutions.
  • Experience with any of the major public cloud formation: AWS (ideally), Azure, GCP

Soft skills:

  • Experience collaborating in cross-functional teams.
  • Excellent English communication skills.
  • Enjoy helping others around you grow as developers and be successful
  • Pick up new ideas and technologies quickly, love learning and talking to others about them
  • Love to experiment and use data and customer feedback to drive decision making


  • Unlimited vacation time — we strongly encourage all of our employees take at least 3 weeks per year
  • A competitive compensation package including stock options
  • Fully remote team — choose where you live
  • Apple laptops provided for new employees
  • Training and development budget for every employee, refreshed each year
  • Parental leave for qualified employees
  • Work with smart people who will help you grow and make a meaningful impact
  • ​​Compensation: base range of 80-110K USD + stock options
  • Work from home stipend! We want you to have the resources you need to set up your home office
  • *drum roll* Company Retreat to Canary Island (if joined to team before AUG 1)