Senior Machine Learning Engineer: ML Recall

Constructor is the next-generation platform for search and discovery in ecommerce, 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 ecommerce 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.

Role Overview

The Machine Learning Recall team builds and optimizes ML/DL models to improve customer experience by providing the best results in terms of relevancy and marginality. We're looking for a Senior MLE who will help us with that.

In the second part of 2025, we plan to focus our attention on:

• Recall: we don't want to lose good results
• Visual solutions: we would like to deliver end-to-end visual solutions for our customer, including image search, shop the look, visual recommendations, etc.
• Technical platform: we have many different technologies/models inside a team, and we would like to allow other teams to use them widely and integrate in their pipelines

Challenges you will tackle

• Build and deploy robust ML systems for search (including text/image & multimodal approaches)
• Tune LLMs to improve our system in different aspects
• Improve business KPIs by using new techniques/models and validating hypotheses
• Collaborate with other technical teams to exchange experiences to improve the overall system
• Be responsible for what you and your team do

Requirements

• 3+ years of professional experience in applied machine learning
• Excellent NLP knowledge (especially transformer-based approaches)
• Comprehensive knowledge of classical machine learning
• Extensive Python knowledge
• Experience with any DL framework (we’re using torch)
• Experience with any SQL dialect (we’re using SparkSQL, MySQL and a couple more dialects)
• You have delivered production ML systems
• Proficiency with big data stack for end-to-end ML product development (we’re using Pyspark for most of our pipelines)
• You are able to translate intuition into data-driven hypotheses that result in engineering solutions that bring significant business value
• Proactivity: you can't close your eyes to problems, but are ready to solve them
• You are friendly and willing to help your teammates

Nice to have:

• Experience designing, conducting, and analyzing A/B tests
• Experience with Rust (or C/C++)
• Experience with a public cloud like AWS, Azure, or GCP
• Strong knowledge of data structures, algorithms and their trade-off
• Empathy
• Ability to explain difficult concepts
• You love to work on performance optimization, such as increasing result quality and improving code performance

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!
• 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
• 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.