Software Engineer 2 (Java/Kotlin/Python) - Search Relevance

About the job

In our domain, we work at the heart of Allegro’s user experience, focusing on what matters most to millions of shoppers every day: search relevance. We are dedicated to ensuring that every search query instantly connects buyers with the best, most accurate offers from a catalog of hundreds of millions of products.

Building and scaling a search engine of this magnitude is a unique engineering challenge rarely found on the market. Our architecture bridges two dynamic worlds: high-performance, low-latency online services built on Java and Kotlin, and an advanced offline processing and Machine Learning ecosystem powered by Python, Apache Airflow, and Google Cloud Platform.

In this role, you will work beyond standard backend CRUD services. You will collaborate closely with research and data science teams to deploy ranking models, build automated evaluation pipelines powered by Large Language Models, and experiment with Generative AI and semantic search features. If you are a backend engineer looking to expand your horizons into real-world AI and ML at massive scale, this team offers the perfect launchpad.

Important things for you

• Flexible working hours in the hybrid model (4/1) - working hours start between 7:00 a.m. and 10:00 a.m. We also have 30 days of occasional remote work.
• The salary range for this position depending on the skill set is as follows (contract of employment, tax-deductible cost):
• PLN 14 600 - 20 825
• Annual bonus based on your annual performance and company results.
• Our team is based in Warszawa.

We are looking for people who

• Code in Java, Kotlin, or Python and have a solid foundation in backend engineering and clean architecture;
• Are open to working at the intersection of backend and AI/ML, combining JVM services with modern machine learning pipelines;
• Care about code quality, building reliable solutions and actively sharing knowledge during code reviews;
• Take an analytical, problem-solving approach to complex challenges affecting millions of active users;
• Value continuous growth and are curious to experiment with modern technologies;
• Communicate in English (at least B2 level);
• Familiarity or curiosity about Machine Learning concepts, data pipelines (Python, Airflow, GCP), or experimenting with LLMs and semantic search.

What's in it for you

• Well-located offices (with e.g. fully equipped kitchens, bicycle parking, terraces full of greenery) and excellent work tools (e.g., raised desks, ergonomic chairs, interactive conference rooms).
• A 16" or 14" MacBook Pro or corresponding Dell with Windows (if you don't like Macs) and all the necessary accessories.
• A wide selection of fringe benefits in a cafeteria plan - you choose what you like (e.g., medical, sports or lunch packages, insurance, purchase vouchers).
• English classes that we pay for related to the specific nature of your job.
• A training budget, inter-team tourism (see more here), hackathons, and an internal learning platform where you will find multiple trainings.
• An additional day off for volunteering, which you can use alone, with a team, or with a larger group of people connected by a common goal.
• Social events for Allegro people - Spin Kilometers, Family Day, Fat Thursday, Advent of Code, and many other occasions we enjoy.

And that's just the beginning! You can read more about the benefits here.

#goodtobehere means that

• You will join a team you can count on - we work with top-class specialists who have knowledge- and experience-sharing in their DNA.
• You will love our level of autonomy in team organization, the space for continuous development, and the opportunity to try new things. You get to choose which technology solves the problem and you are responsible for what you create.
• You will value our Developer Experience and the full platform of tools and technologies that make creating software easier. We rely on an internal ecosystem based on self-service and widely used tools such as Kubernetes, Docker, Consul, GitHub, and GitHub Actions. Thanks to this, you can contribute to Allegro from your very first days on the job.
• You will be equipped with modern AI tools to automate repetitive tasks, allowing you to focus on developing new services and refining existing ones (also leveraging AI support).
• You will create solutions that will be used (and loved!) by your friends, family and millions of our customers.
• You will meet the Allegro Scale, which starts with over 1000 microservices, an open-source data bus (Hermes) with 300K+ rps, a Service Mesh with 1M+ rps, tens of petabytes of data, and production-used machine learning.
• You will become part of Allegro Tech - We speak at industry conferences, cooperate with tech communities, run our own blog (it's been over 10 years!), record podcasts, lead guilds, and we organize our own internal conference - the Allegro Tech Meeting. We create solutions we love (and can) to talk about!

Send us your CV and… see you at Allegro!