Senior Software Engineer (Java / Kotlin) - Allegro Ads

Our requirements

• Code in Kotlin or Scala and have experience with Spring Boot and Kafka to build robust backend systems;
• Have hands-on experience with Apache Airflow and Spark, enabling them to manage high-velocity data pipelines and build scalable reporting engines;
• Are proficient in PostgreSQL and have experience with database migrations and designing integrations via APIs;
• Enjoy close collaboration with Data Scientists and Analysts, working together to implement complex models and turn raw data into actionable insights;
• Are enthusiastic about AI and want to stay at the forefront of technical innovation;
• Want to build impactful tools for a diverse range of users, helping them understand campaign performance through advanced statistics and dashboards;
• Experience with frontend technologies (React/TypeScript) is a “Nice to have” to help build modern frontend reporting components;
• Are excited to join a growing team where they can influence the technical vision and help shape new projects from the ground up within the ecosystem;
• Know English at at least B2 level.

Your responsibilities

• Massive Scale: Design, build, and optimize systems that handle thousands of requests per minute. This is high-availability, high-performance engineering in practice.
• Modern Tech Stack: Work with a world-class, cloud-native environment. Our core technologies include Kotlin, Spring, Kafka, and Kubernetes. We're not shy when it comes to ML too :)
• True Ownership & Autonomy: We live by a "you build it, you run it" philosophy. You'll join an agile, autonomous team with full ownership of your microservices, from design to deployment.
• Complex Challenges: From distributed systems and data streaming to algorithmic optimization, you'll tackle the complex backend problems that power a massive, real-time marketplace.
• End-to-End ML Systems: Bridge the gap between big data and real-time product impact. You’ll build the infrastructure using BigQuery and Apache Spark for offline data processing. You’ll integrate these components with our microservices architecture to create the sophisticated advertising system that powers a personalized user experience.

About the project

#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!

What we offer

• 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.

Benefits

• sharing the costs of sports activities
• private medical care
• sharing the costs of foreign language classes
• sharing the costs of professional training & courses
• life insurance
• flexible working time
• integration events
• no dress code
• leisure zone
• extra social benefits