Senior Software Engineer (Java / Kotlin) - Allegro Ads

Allegro; Warszawa; Hybrid; PLN 210,366 - 289,044; Full time

Benefits offered by this job

MacBook Pro or Dell with Windows

Fringe benefits cafeteria plan

English classes

Training budget

Volunteer day off

Social events

Job summary

Allegro, Warsaw-based tech company, seeks skilled backend engineers to design, build, and optimize large-scale systems powering a real-time marketplace.

You will own microservices from design to deployment, work with a modern cloud-native stack, and collaborate with ML/DS teams to translate data into impactful product features. Hybrid work in Poland and a strong focus on performance and autonomy are offered.

Qualifications

• Proficient in Kotlin/Scala with backend focus.
• Experience with Spring Boot and Kafka.
• Hands-on experience with Apache Airflow and Spark for data pipelines.
• Strong PostgreSQL knowledge; experience with API integrations.
• Collaborates with Data Scientists/Analysts to turn data into insights.
• Interest in AI and real-time, scalable systems.
• Nice to have frontend experience (React/TypeScript).

Responsibilities

• Design, build, and optimize high-availability backend systems.
• Own microservices from design to deployment (you build it, you run it).
• Develop end-to-end ML/inference pipelines and real-time analytics.
• Collaborate with ML/Data Science teams to enable data-driven product features.
• Contribute to Allegro Ads backend powering a massive marketplace.

Skills

Kotlin

Scala

Spring Boot

Kafka

React

TypeScript

English (B2)

Tools

Apache Airflow

Spark

PostgreSQL

Kubernetes

Docker

BigQuery

Job description

• 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.

Join the Advertising team! You will have a chance to build Allegro Ads - one of the most visible products on the platform. Your team works closely with the Machine Learning team, creating the best experience for customers. High performance, engineering best practices and great atmosphere in the team guaranteed!

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 18 850 - 25 900
• Annual bonus based on your annual performance and company results.
• Our team is based in Warsaw.

We are looking for people who

• 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.

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.

#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!