April 24, 2026
Team Leader (Java / Kotlin) - Recommendations Team
Senior • Hybrid
Warsaw, Poland
About the role
Join the Recommendation team! You will have a chance to build tools for recommendations on Allegro - one of the most visible products on the platform. Your team work closely with the Machine Learning team, creating the best experience for customers. High performance, engineering best practices and great atmosphere in the team guaranteed!
We are looking for a leader who is still close to technology. In this role, you will spend around 20-50% of your time on technical work (coding, code reviews, architecture), with the remaining time focused on team development and business collaboration.
Important things for you
Contract of employment, tax-deductible costs
-
Depending on your annual assessment and the company's results we offer:
Annual bonus based on your annual performance and company results.
Long term discretionary incentive plan based on Allegro.eu shares (restricted stock units).
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.
Our team is based in Warsaw.
What will you do?
Lead the development team (5-7 members) – ensuring accurate, scalable, and reliable delivery predictions
Technical leadership – mentoring, code reviews, ensuring high code quality
Design and implementation of key systems (languages: Scala, Java/Kotlin, Python, stacks: Spring Boot, Apache Pekko, Apache Spark, Google Cloud Platform)
Collaboration with cross-functional teams - data science, data engineering, analytics, UX, operations
Ensuring high quality - clean code, code review, TDD, CI/CD to ensure the quality and maintainability
Who are we looking for?
Experience in leading a team (Java/Kotlin and/or Scala) as a Tech Lead or Team Leader
Still actively coding and eager to maintain technical expertise
Strong knowledge of engineering best practices (testing, CI/CD, scalable architecture)
Experience with high-traffic distributed systems and data engineering
Ability to bridge technical and business perspectives
Proficiency in English (B2+)
Nice to have
Experience with ML
Familiarity with GCP data engineering tools: BigQuery, Cloud Composer, Dataproc
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!
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Allegro
Software Engineer 1 (Java/Kotlin) - Competitive Price
Junior
Hybrid
Warsaw, Poland
10,700 - 14,900 PLN/mo
🏢 Summary: Backend Engineer role focused on designing and operating high-availability, high-performance microservices in a massive-scale, cloud-native environment. The position involves building distributed systems and real-time data solutions using Java/Kotlin and modern technologies on GCP. You will own services end-to-end in an autonomous team following a "you build it, you run it" approach. 🗂️ Requirements: Proficiency in Java or Kotlin, Willingness to develop in Kotlin, Experience with microservices architecture, Experience with distributed systems, Experience with cloud environments (GCP), Knowledge of Spring framework, Experience with databases (NoSQL), Ability to work with high-load systems, English level B2 or higher 📃 Skills: Java, Kotlin, Spring, MongoDB, GCP, Microservices, React, Airflow, BigQuery, Kubernetes, Docker, Consul, GitHub, GitHubActions 🏢 Description: About the job 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 (GCP). Our core technologies include Java, Kotlin, Spring, MongoDB, microservices, React, Airflow (BigData). 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. About us We are the team behind Allegro Prices - one of our most important pricing programs. As part of the Competitive Price unit, we build its logic and grow its reach to keep our prices competitive. Our main goal is to ensure great deals on the products that shoppers actually look for. We do this at scale using full automation and data from many different sources Important things for you Flexible working hours in the hybrid model (4/1) - working hours start between 7:00 a.m. and 09:30 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 10 700 - 14 900 Annual bonus based on your annual performance and company results. Our team is based in Kraków and Warsaw. We are looking for people who: Code in Kotlin or Java and are eager to master Kotlin by taking part greenfield project Have a natural curiosity for new technologies and a desire to become a well-rounded engineer by exploring our modern stack, including React, Airflow and BigQuery; Want to be proud of the code they create ; they value high-quality code reviews and engage in substantive discussions on software engineering best practices; Are excited about building new products and want to experience the journey of launching a fresh project within the Allegro ecosystem; Are open to developing soft skills and exploring a full-stack mindset by learning new backend and frontend Can look for effective solutions to the requirements set by users; Want to constantly develop and update their knowledge; 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. 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!
Technology
Allegro
Software Engineer 1 (Java / Kotlin)
Junior
Hybrid
Torun, Poland
10,700 - 14,900 PLN/mo
🏢 Summary: Backend engineering role focused on designing, building, and operating high-availability microservices handling massive scale in a cloud-native environment. The position involves solving complex distributed systems and data streaming challenges using modern technologies such as Kotlin, Spring, Kafka, and Kubernetes. You will own services end-to-end, ensuring scalability, stability, and high data quality within a real-time marketplace platform. 🗂️ Requirements: Proficiency in Kotlin or Java, Experience building microservices, Experience with distributed systems, Experience with data streaming systems, Experience with cloud-native architectures, Ability to design high-availability and high-performance systems, English proficiency at B2 level or higher 📃 Skills: Kotlin, Java, Spring, Kafka, Kubernetes, Docker, Consul, GitHub, GitHubActions, Microservices, DistributedSystems, DataStreaming, REST, ML 🏢 Description: About the job: 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. In our domain, we focus on solutions centered around the product catalogue , a critical component within Allegro's core partner journey. We approach quality with particular diligence to ensure stability, scalability and simplicity of the offer listing process. Moreover, product catalogue data quality is crucial for correctness of internal Allegro processes. We work in cross-functional teams where various technologies collaborate closely to deliver the highest quality solutions to our users. Our teams consist of backend engineers and frontend specialists with support of project managers, UX-designers and data scientists. 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 10 700 - 14 900 Annual bonus based on your annual performance and company results. Our team is based in Toruń. We are looking for people who: Code in Kotlin or Java ; Expect work that has a deeper meaning (not only tasks "management has commissioned") and want to enjoy its results; Want to be proud of the code they create. They eagerly accept comments and share knowledge during code reviews; Can look for effective solutions to the requirements set by users; Want to constantly develop and update their knowledge; 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. 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!
Technology
Allegro
Senior Software Engineer (Java / Kotlin)
Senior
Hybrid
Poznan, Poland
18,400 - 25,450 PLN/mo
🏢 Summary: Design and develop high-performance, cloud-native backend systems powering large-scale search and recommendation services. Work in an autonomous team owning microservices end-to-end in a distributed, real-time marketplace environment. Solve complex challenges in data streaming, search optimization, and machine learning at massive scale. 🗂️ Requirements: Proficiency in Kotlin or Java, Experience with backend development, Understanding of distributed systems, Experience with microservices architecture, Ability to design high-performance systems, English B2 level or higher, Participation in code reviews, Ownership of services from design to deployment 📃 Skills: Java, Kotlin, Spring, Kafka, Kubernetes, Vespa, Lucene, Solr, Docker, Consul, GitHub, GitHubActions, Microservices, DistributedSystems, MachineLearning, LLM, LoRA, PEFT, LangChain, AutoGen, CrewAI 🏢 Description: Senior Software Engineer (Java / Kotlin) Location: Poznań, PL, 61-569 Company: Allegro sp. z o.o. Team: Technology Contract Type: Employee About the job Massive Scale : Design, build, and optimize systems that handle thousands of requests per second. 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. On the back side, there is Vespa and a highly optimized and heavily customized Lucene/Solr installation. 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; and improvements are dictated by results of our own experiments. 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. And a constantly modernizing approach to search solutions will give you the opportunity to work with advanced embedding and ranking models and pipelines. In our domain we focus on delivering search results for multiple Allegro services, from search result pages, to recommendations, to offers comparisons in various placements. We maintain a critical entry point for users’ search experience through a huge catalog of products and offers, striving for relevancy first. To deliver, we are designing, implementing and operating an extensive system combining modern microservice architecture with high performance backends and vast data sources. We care about data quality and availability and strive for near real-time accuracy, to best guide users to products and offers in a highly dynamic marketplace. 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 18 400 - 25 450 Annual bonus based on your annual performance and company results. Long term discretionary incentive plan based on Allegro.eu shares (restricted stock units). Our team is based in Poznań. We are looking for people who: Code in Kotlin or Java ; Expect work that requires creative approach to search experience challenges, to be proud of enjoying its results together with all Allegro users; Want to create solid code, eagerly accept comments and share knowledge during code reviews; Can look for effective solutions to the requirements set by users; Want to constantly develop and update their knowledge; Know English at at least B2 level. Nice to have: You are open to diverse technologies and workflows, including dev-operational tools on one hand, and working with data on the other. Basic experience with LLM tuning (LoRA, PEFT), training and evaluation pipelines for models and/or basic frameworks for building AI Agents (LangChain, AutoGen, CrewAI) would be great! 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!
Technology
Allegro
Software Engineer 2 (Java / Kotlin) - Product Catalog
Mid
Hybrid
Torun, KP, Poland
14,600 - 20,825 PLN/mo
🏢 Summary: Backend Software Engineer role focused on developing and optimizing Product Catalog solutions, particularly duplicate detection and product grouping at scale. The position involves designing and maintaining backend services and architectures in a cloud-based, microservices environment using Kotlin and JVM technologies. You will work on high-scale systems, contributing to core platform components and automation. 🗂️ Requirements: Commercial experience in Kotlin development, Strong knowledge of backend architectural patterns, Experience designing and maintaining backend services and APIs, Ability to design software architectures, Experience with debugging and resolving software defects, Fluent Polish (C1), English proficiency (B2), Experience working with distributed systems at scale 📃 Skills: Kotlin, JVM, Kubernetes, Docker, Consul, GitHub, GitHubActions, Microservices, APIs, Cloud, Hermes, ServiceMesh 🏢 Description: About the job In this role, you will be a key player in evolving our Product Catalog - the foundational pillar of our platform. Your primary objective will be to build and optimize solutions for duplicate detection and accurate product grouping across a broad portfolio of system components. Your work will directly shape the daily experience of our users. You will ensure Buyers enjoy a high-quality, clutter-free shopping experience, while helping Partners list their products more efficiently. Expect to tackle exciting technical challenges at scale, working with a diverse tech stack that includes online JVM services and offline processing in a public-cloud environment. 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 gross 14 600 - 20 825 Annual bonus based on your annual performance and company results. Our team is based in Toruń. What You'll Do: Design, develop, test and maintain high-quality code for backend services, APIs and automation scripts. Debug and resolve software defects and issues. Design and develop new project architectures while proposing better architectural approaches for existing solutions. Share knowledge with team members and support junior engineers. Collaborate with product managers, data analysts, UX designers and fellow engineers to gather and refine requirements. Support on-call engineers by participating in the Software Engineer role on-call rotation. Write clean, efficient and well-documented code. We are looking for someone who has: Solid commercial experience in Kotlin development and a strong command of backend architectural patterns. Language proficiency in Polish at a C1 level and English at a B2 level. Excellent problem-solving and decision-making skills, paired with a Data-Driven mindset. High learning agility, adaptability to change, flexibility and strong skills in communication and cooperation. 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!
Technology
Allegro
Software Engineer 1 (Java / Kotlin)
Junior
Hybrid
Warsaw, Poland
10,700 - 14,900 PLN/mo
🏢 Summary: Backend engineering role focused on designing and operating high-availability, large-scale microservices in a cloud-native environment using Kotlin and modern distributed systems technologies. The position involves full ownership of services, building real-time systems, data streaming solutions, and AI-powered customer experience products. Engineers work on complex backend challenges within a highly autonomous, agile team. 🗂️ Requirements: Proficiency in Kotlin or Java, Willingness to develop in Kotlin in greenfield projects, Experience building high-availability and high-performance systems, Experience with distributed systems and microservices architecture, Ability to design, build, deploy, and operate services end-to-end, Experience with data streaming systems, English level B2 or higher 📃 Skills: Kotlin, Java, Spring, Kafka, Kubernetes, Docker, Consul, GitHub, GitHubActions, Microservices, DistributedSystems, DataStreaming, MachineLearning, AI 🏢 Description: About the job 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. In our Customer Experience (CX) domain, we focus on creating a seamless and intuitive contact journey for our users. Our mission is to elevate the support experience by developing the core contact path, integrating diverse communication channels, and implementing our cutting-edge AI Assistant to provide smart, instant resolutions. We also own and manage the platform's central survey engine, which empowers the business to gather crucial user feedback and continuously shape our strategy. We take full end-to-end ownership of our products, allowing us to build scalable, high-performing systems that directly impact user satisfaction and adapt to evolving business needs. We work in cross-functional teams where diverse technologies converge to drive Allegro’s success. Our team consists of backend and frontend specialists, collaborating closely with Product Managers, UX Designers, and AI/Data specialists. 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 10 700 - 14 900 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 Java and are eager to master Kotlin by taking part greenfield project Want to be proud of the code they create ; they value high-quality code reviews and engage in substantive discussions on software engineering best practices; Are excited about building new products and want to experience the journey of launching a fresh project within the Allegro ecosystem; Are open to developing soft skills and exploring a full-stack mindset by learning new backend, frontend, and mobile technologies; Are open to incorporating AI coding assistants into their daily work to maximize efficiency and focus on complex problem-solving Can look for effective solutions to the requirements set by users; Want to constantly develop and update their knowledge; 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. 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!