Senior Machine Learning Engineer: Ranking

Constructor is the next-generation platform for search and discovery in e-commerce, built to explicitly optimize for metrics like revenue, conversion rate, and profit. Our search engine is entirely invented in-house utilizing transformers and generative LLMs, and we use its core and personalization capabilities to power everything from search itself to recommendations to shopping agents. Engineering is by far our largest department, and we've built our proprietary engine to be the best on the market, having never lost an A/B test to a competitive technology. We're passionate about maintaining this and work on the bleeding edge of AI to do so.

Out of necessity, our engine is built for extreme scale and powers over 1 billion queries every day across 150 languages and roughly 100 countries. It is used by some of the biggest e-commerce companies in the world like Sephora, Under Armour, and Petco.

We're a passionate team 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 do best can lead to great things.

Constructor is a U.S. based company that has been in the market since 2019. It was founded by Eli Finkelshteyn and Dan McCormick who still lead the company today.

The Ranking team, within the Machine Learning chapter, plays a central role in implementing algorithms that optimize our customers' business KPIs like revenue and conversion rates. We focus on metrics over features, supplying our ranking algorithms with powerful capabilities that bring value to our customers. 

As a member of the Ranking team, you will be encouraged to use world-class analytical, engineering, and machine learning techniques on big data to scale our ranking algorithms. The Ranking team owns all stages of product ranking for Constructor's Search, Browse, and Autocomplete experiences, including base ranking, ML ranking, personalization, and ranking explanation.

A primary focus of the Ranking team is to develop a high-quality ranking system that satisfies business needs and accounts for behavioral user patterns. Related to that focus, the Ranking team owns: 

• An online high load distributed REST based ranking service deployed in the cloud and developed in the Python programming language, receiving around 55 million requests a day.
• Offline Data Pipelines that are used for data processing (Python, Spark/ Databricks), ML model training and model signals delivery (e.g. Feature Store), Ranking configuration for any given customer.
• Ranking Quality monitoring tools to measure relevance, personalization, attractiveness, diversification, and other quality signals.

As a Machine Learning Engineer on the Ranking team, your primary focus will be to enhance the quality of our ranking systems, ensuring that search, browse, and autocomplete experiences are highly relevant, personalized, and diverse. You will work on building state-of-the-art ranking algorithms that improve user experience and drive critical business metrics such as conversion, user engagement, and revenue growth.

In addition to improving ranking quality, you will ensure that our solutions can be deployed in real-time environments, handling high-throughput requests efficiently while maintaining low-latency performance. Our ranking system processes thousands of requests per second, and maintaining both quality and speed is essential for our global customers, who rely on fast, accurate results.

The job can consist of, but is not limited to:

• Design and Develop ML-Based Ranking Solutions: build, deploy, and optimize machine learning models to enhance search engine ranking systems, driving improvements in key business metrics such as conversion, engagement, and user satisfaction.
• Improve Ranking Quality: analyze ranking performance and identify gaps in search, browse, and autocomplete experiences, focusing on relevance, personalization, attractiveness, diversification, and other quality signals.
• Innovate and Optimize Ranking Algorithms: proactively propose new machine learning models, algorithms, and features to advance the ranking pipeline, improve ranking quality, and meet evolving business needs.
• Collaboration with Cross-Functional Teams: collaborate with technical and non-technical business partners to develop / update ranking functionalities (both within and outside the team)

Hard skills

• At least 4 years of experience with Python for machine learning and backend development
• At least 4 years of experience developing, deploying, and maintaining machine learning models with a strong focus on ranking systems for search, recommendations, or similar applications
• Experience in large-scale ML model training, evaluation, and optimization, with a focus on real-time inference and serving
• Experience with big data frameworks such as Spark for processing large datasets and integrating them into ML pipelines
• Proficiency in using tools like SQL, PySpark, Pandas, and other frameworks to extract, manipulate, and analyze data
• Experience with data pipeline orchestration tools like Airflow or Luigi to manage and automate workflows for ML training and signal delivery
• Experience working on ranking algorithms that optimize metrics such as relevance, conversion rates, personalization, user engagement, RPV is a plus

Soft skills

• Experience collaborating in cross-functional teams
• Experience leading projects to success 
• 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
• 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
• This position has a base salary range between $80k and $120k USD. The offer varies on many factors including job related knowledge, skills, experience, and interview results.
• Regular team offsites to connect and collaborate

Diversity, Equity, and Inclusion at Constructor

At 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.