--- title: 'BackEnd Engineer: Experiments at Constructor' canonical: 'https://feeny.ai/job/backend-engineer-experiments-constructor-spain-9bk6q9apt3fy' type: 'job' last_seen: '2026-09-11' --- # BackEnd Engineer: Experiments at Constructor - **Company:** Constructor - **Location:** Spain - **Employment:** full-time - **Work type:** remote - **Posted:** 2026-07-06 - **Last confirmed live:** 2026-09-11 - **Apply:** https://jobs.ashbyhq.com/constructor/4e7cfde4-c2ba-4251-b95f-7bcf9793984a ## Job description ## About us 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. ## About the Team The Experiments team at Constructor builds an experimentation platform: traffic allocation, exposure logging, metric computation, statistical analysis, and a UI for launching experiments and interpreting results. It’s used both internally and by customers running experiments on production traffic. We’re scaling customer experimentation usage and investing in making experiments faster, more reliable, and easier to interpret. Unlike boxed experimentation tools, our platform has to support a wide range of customer integrations, traffic patterns, and industry constraints — which makes the engineering problems unusually real-world and high-leverage. Team: 3 Software Engineers, 1 Data Analyst, an Engineering Manager, and a Product Manager. ## The Role This is primarily a backend role (Python services + data-heavy systems). You’ll occasionally work in the Dash UI and contribute to Spark jobs, but those are not the main focus. We care about correctness, observability, and product usability more than complex infrastructure. Tech: Python, FastAPI, PostgreSQL, Plotly Dash, PySpark/Databricks, AWS, CloudWatch, Sentry (Spark work is ~5–10% — we don’t expect you to be a data engineer or own the data platform.) ## What you’ll do - Build and maintain backend services for experiment assignment, logging, and report generation - Improve scalability, performance, and reliability of experiment reporting pipelines - Add product-facing features to the UI to help users launch experiments and interpret results - Take technical ownership of projects: shape solutions, break down work, and drive execution with the team - Participate in a weekly on-call rotation (investigating occasional issues and answering internal questions) You’ll collaborate closely with Search/Recommendations engineers, ML/DS partners, and customer-facing teams when needed. This role does not require frequent direct customer calls. ## Requirements Must-have - Strong experience building and owning production backend services in Python - Experience with monitoring, alerting, and debugging user-facing systems - Strong SQL skills and confidence working with data-heavy systems (metrics, logging, analytics) - Ability to ship maintainable software (tests, code review, incremental delivery) Mindset - You take ownership: you can turn ambiguous problems into an executable technical plan - You care about building systems people trust and rely on Nice-to-have - Experience with experimentation systems, metrics platforms, or A/B testing workflows - Experience with PySpark and/or Databricks - We don’t expect you to already be an expert in experimentation methodology — but we do expect strong backend fundamentals and the ability to ramp up effectively in a data-heavy domain Location / Time Zones - We’re a distributed team. Preferred time zones are UTC+1 to UTC+7, but we’re flexible ## Benefits - 🏝️ Unlimited vacation time - we strongly encourage all employees to 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 - refreshed each year for every employee - 👪 Maternity & Paternity leave for qualified employees - 🧠 Work with smart people who will help you grow and make a meaningful impact - 💵 Base salary: $80k–$110k 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](http://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. ## About Constructor ## Core Business - **Primary industry**: AI-powered ecommerce search and product discovery (SaaS) - **Target customers**: B2B, enterprise ecommerce brands, retailers, distributors, and marketplaces - **Mission/purpose**: To automate the rich complexity required for a modern search experience behind a simple, elegant SaaS solution, helping shoppers find what they want to buy using natural language and AI. ## Products & Services - **AI Shopping Agent**: Natural language conversational agent that helps shoppers discover products and answer questions. - **Search & Browse**: Personalized search and category browsing with reinforcement learning. - **Recommendations**: Product recommendations for onsite, email, SMS, and mobile notifications. - **Retail Media**: Sponsored products and ads that don’t sacrifice customer experience. - **Merchandiser Controls**: Tools for merchants to manage rankings, promotions, and experiments. - **Insights & Automations**: Dashboards, reports, and automated attribute enrichment using GenAI. - **Answer Engine Assistants (Beta)**: Integration with ChatGPT and other answer engines for offsite discovery. - **Merchant Intelligence Agent (Beta)**: Research and fix ranking issues. - **Product Insights Agent**: Generate personalized product questions to help shoppers buy with confidence. - **Collections**: Dynamic, curated product pages. - **In-Store**: Extend online intelligence to physical stores. ## Market Standing - **Valuation/Market Cap**: Not disclosed (private) - **Key Metric**: $40.0M annual revenue (LinkedIn estimate); $86.1M total funding across 4 rounds - **Notable Investors/Partners**: Not named in provided sources, but clients include Sephora, Under Armour, Petco, and many others. - **Growth Signals**: - 336 employees (LinkedIn) / 375+ team members (company site), +48% YoY headcount growth - 400+ billion requests powered per year - 98.5% average client retention rate over the last three years - Named a Leader in Forrester Wave (Commerce Search & Product Discovery, Q3 2025), Gartner Magic Quadrant (Search & Product Discovery, 2025), and IDC MarketScape - Top rated on G2 Crowd and Gartner Peer Reviews (4.9 and 4.8 respectively) - 94% team member retention rate ## Competitive Advantages - **AI-native from day one**: Built on clickstream data and advanced AI, not bolted onto legacy keyword search. - **Reinforcement learning across touchpoints**: Every interaction (search, browse, agent) makes the system smarter. - **API-first, headless, composable, platform-agnostic**: Easy integration with any tech stack. - **Ecommerce-specific optimization**: Sole focus on commerce metrics (revenue, conversion, profit), consistently delivering $10M+ revenue lifts for customers. - **Only vendor named a Leader by three independent analyst firms (Forrester, Gartner, IDC)**. ## Strategic Focus - **AI agents and reasoning**: Expanding AI Shopping Agents, Answer Engine Assistants, and Merchant Intelligence Agents. - **Offsite discovery**: Enabling discovery via email, SMS, and answer engines like ChatGPT. - **In-store integration**: Extending online intelligence to physical retail. - **Continued investment in personalization and automation** to reduce setup time (8 weeks or less). ## Why Work Here - **Culture**: Remote-first, 100% remote – choose where you live. Collaborative, empathetic, and problem-solving environment. Rated top 5% on RepVue and a Will Reed Top 100 award recipient. - **Benefits**: - Company pays 99% of medical, dental, and vision premiums for US team members. - Unlimited PTO and vacation time (minimum 3 mandatory weeks off per year). - Paid parental leave. - Yearly Remote Work Stipend + one-time $500 New Hire Setup Stipend. - Yearly Learning & Development $500 Stipend. - Stock options for every team member. - Company-issued Apple laptop. - **Growth**: Fast-growing startup with opportunities to work on challenging AI/ML problems used by millions of shoppers. Mentorship, autonomy, and career development. - **Diversity & Inclusion**: Committed to DEI with an internal ERG. - **Team**: 94% retention rate; described as collaborative, brilliant people who enjoy solving hard problems. ## Sources 1. [Constructor Careers Page](https://constructor.com/about/careers) 2. [Constructor Main Website](https://constructor.com/) 3. [Constructor LinkedIn](https://www.linkedin.com/company/constructor-io) 4. [Constructor About Page](https://constructor.com/about) 5. [CB Insights Company Profile](https://www.cbinsights.com/company/constructorio) (used for funding and revenue data, though not directly cited in text – revenue from LinkedIn) ## Other roles at Constructor - [Staff Product Manager: Product Discovery Engine](https://feeny.ai/job/staff-product-manager-product-discovery-engine-constructor-remote-gb8a7v1gkqah) - [Customer Success Enablement Manager](https://feeny.ai/job/customer-success-enablement-manager-constructor-amer-pvkxtwm1yxws) — AMER - [Senior Customer Success Manager - Nordics](https://feeny.ai/job/senior-customer-success-manager-nordics-constructor-sweden-q7mbnfe85d9b) — Sweden - [Sr. Customer Success Manager (French Speaking)](https://feeny.ai/job/sr-customer-success-manager-french-speaking-constructor-france-n0809w6gb2v2) — France - [FullStack Engineer - Prospect UI Solutions](https://feeny.ai/job/fullstack-engineer-prospect-ui-solutions-constructor-remote-g6jgr2q79412) - [Director of Information Security](https://feeny.ai/job/director-of-information-security-constructor-emea-3qbt89fc9ne7) — EMEA - [Account Manager, DACH](https://feeny.ai/job/account-manager-dach-constructor-emea-wc72h030b83v) — EMEA - [Technical Support Engineer](https://feeny.ai/job/technical-support-engineer-constructor-emea-fxdcvm2eq3fa) — EMEA - [Engineering Manager - Customer Developer Experience](https://feeny.ai/job/engineering-manager-customer-developer-experience-constructor-remote-v1y9wfa27acx) - [Engineering Manager: Agentic Integrations](https://feeny.ai/job/engineering-manager-agentic-integrations-constructor-remote-s5hw0am1dwnx)