Senior Software Engineer (Java/Kotlin)

🏢 Summary: The role focuses on designing and delivering high-complexity, scalable backend solutions in a large-scale distributed ecosystem, combining deep Kotlin expertise with AI-driven capabilities such as LLM integrations. The engineer will drive architectural decisions, ensure production-grade quality, and integrate agentic AI systems into real-world workflows. This position requires strong ownership, autonomy, and impact on systems operating at significant scale. 🗂️ Requirements: Proven experience as Senior Software Engineer in high-scale environments, Deep hands-on experience with Kotlin, Commercial experience with LLM integration, Experience with agentic systems or frameworks, Strong system design and architectural skills, Experience with scalability, performance, and reliability, Experience ensuring observability of distributed systems, Ability to manage technical debt and system risks, Experience integrating AI solutions into production systems 📃 Skills: Kotlin, LLM, AI, Agentic, Architecture, Scalability, Performance, Observability, DistributedSystems, GCP, Kubernetes 🏢 Description: Senior Software Engineer (Kotlin / AI Integration / Large-Scale Systems) We are looking for a highly experienced Senior Software Engineer to join a large-scale product ecosystem operating in a complex, distributed environment. This role is designed for a strong Individual Contributor who thrives on solving high-complexity problems, influencing architecture, and delivering scalable, production-grade solutions. You will work at the intersection of modern backend engineering and AI-driven capabilities, helping evolve systems that operate at significant scale. The ideal candidate combines deep Kotlin expertise with curiosity and practical interest in AI-powered solutions — particularly LLM integrations and agentic frameworks — and understands how to translate technical decisions into real user impact. What You’ll Be Responsible For Designing and delivering high-complexity features and system components Driving architectural decisions and evaluating technical trade-offs Ensuring quality, scalability, reliability, and observability of delivered solutions Taking end-to-end ownership of implementation, from concept to production Identifying and managing technical risks, dependencies, and technical debt Integrating AI-driven capabilities (LLMs, agentic systems) into production workflows Collaborating closely with Engineers, Product Managers, and Designers Evaluating technical decisions based on measurable user impact Operating with high autonomy and accountability in a mature engineering environment Must Have Proven experience as a Senior Software Engineer delivering complex, high-scale solutions Deep hands-on experience with Kotlin Basic commercial experience and strong interest in AI-driven solutions , especially LLM integration and Agentic Systems/Frameworks Strong architectural mindset and ability to drive system design Experience managing scalability, performance, stability, and observability Ability to identify technical debt and proactively address system risks Strong collaboration and communication skills High level of ownership and autonomy Nice to Have Experience with Cloud environments (GCP preferred) and Kubernetes Experience working with large-scale distributed systems Cross-team collaboration in complex organizational structures Providing technical consultancy and knowledge sharing within teams Advising on engineering standards and continuous optimization of development practices

🏢 Summary: Senior Backend Engineer role focused on building and scaling a cloud-based SaaS platform using modern .NET services and REST APIs. The position involves designing distributed systems, improving reliability and observability, and working with cloud and container environments. You will contribute to technical decisions and engineering best practices within a collaborative team. 🗂️ Requirements: 5+ years backend development experience, Experience with SaaS and web applications, Strong knowledge of C#, Strong knowledge of modern .NET/.NET Core, Solid computer science fundamentals, Experience with distributed systems design, Experience with cloud platforms, Experience with containers and orchestration, Understanding of concurrency and performance, Knowledge of authentication and authorization mechanisms 📃 Skills: C#, .NET, .NETCore, REST, Azure, AWS, GCP, Kubernetes, Kafka, RabbitMQ, SQS, Docker, SQL, HTML, CSS, JavaScript 🏢 Description: We’re hiring a Senior Backend Engineer to help build and scale a cloud-based SaaS platform. You’ll work on modern .NET services and APIs, improve reliability and observability, and contribute to technical decisions as part of a collaborative engineering team. Responsibilities: Build and maintain backend services and REST APIs in C# / .NET (.NET Core). Design scalable solutions for distributed systems (async workflows, messaging, integrations). Work with cloud services (Azure/AWS/GCP) and container environments (e.g. Kubernetes). Strengthen system reliability with logging, metrics, tracing, and monitoring. Support secure access patterns: authentication/authorization, API gateway concepts. Contribute through code reviews, good engineering practices, and automation. Requirements: 5+ years of backend development experience, including SaaS and web applications. Strong knowledge of C# and modern .NET + solid CS fundamentals. Familiarity with containers/orchestration and cloud-native approaches. Experience with some of: Kafka/RabbitMQ/SQS, workflow orchestration, job scheduling, search. Good understanding of concurrency and performance. Strong communication skills; Agile/Scrum is a plus. Bonus: basic front-end knowledge (HTML/CSS/JS).

🏢 Summary: Senior Software Engineer role focused on building scalable front-end and cloud-native applications, with flexibility for deep specialization in modern front-end technologies or AWS cloud engineering. The position involves designing serverless architectures, integrating APIs, managing databases, and implementing CI/CD pipelines in a collaborative environment. Regular on-site presence and strong English communication skills are required. 🗂️ Requirements: Minimum 8 years of commercial software development experience, Strong expertise in front-end development with component-based frameworks or AWS cloud engineering, Hands-on experience designing and delivering cloud-native applications, Experience with serverless architectures, Solid understanding of API design principles and distributed systems, Experience with CI/CD pipelines and deployment automation, Ability to communicate fluently in English, Availability for regular on-site work 📃 Skills: JavaScript, TypeScript, AWS, Serverless, REST, SQL, NoSQL, CI/CD, Docker, Kubernetes 🏢 Description: We are looking for a highly experienced Software Engineer with strong expertise in modern front-end technologies and cloud-based solutions. In this role, you will be responsible for designing and delivering scalable, high-quality applications in a highly collaborative and fast-paced environment. The position requires regular on-site presence and the ability to communicate effectively in English with both technical and non-technical stakeholders. Depending on your strengths, we welcome candidates with either deep front-end specialization or strong hands-on experience in cloud engineering, ideally combining both. Your tasks Develop and maintain applications using modern front-end technologies and strongly typed languages Design and implement scalable cloud-based architectures, including serverless solutions Build and integrate RESTful services to support application functionality Work with both relational and non-relational databases to manage and process data effectively Create and optimize automated deployment pipelines for continuous integration and delivery Collaborate with stakeholders to translate business requirements into technical solutions Requirements Minimum 8 years of commercial experience in software development using modern programming languages Strong hands-on expertise in either front-end development (including component-based frameworks) or cloud engineering (AWS) Practical experience designing and delivering cloud-native applications, preferably in a serverless environment Solid understanding of API design principles and best practices for distributed systems Experience working with CI/CD pipelines and deployment automation tools Excellent communication skills with the ability to explain technical concepts clearly, and fluency in English What we offer Great Place to Work since 2015 - it’s thanks to feedback from our workers that we get this special title and constantly implement new ideas Employment stability - revenue of PLN 2.1BN, no debts, since 2006 on the market We share the profit with Workers - over PLN 76M has already been allocated for this aim since 2022 Attractive benefits package - private healthcare, benefits cafeteria platform, car discounts and more Comfortable workplace – class A offices or remote work Dozens of fascinating projects for prestigious brands from all over the world PLN 1 000 000 per year for your ideas - with this amount, we support the passions and voluntary actions of our workers Investment in your growth – meetups, webinars, training platform and technology blog – you choose Fantastic atmosphere created by all Sii Power People If you want to work on systems with high operational significance — apply now!

🏢 Summary: The role focuses on building and evolving core platform services to support engineering teams, emphasizing scalable cloud-native solutions, developer experience, and automation. It involves designing shared services, advancing CI/CD and Infrastructure as Code practices, and integrating AI-powered tools and LLM-based solutions. The position also promotes DevOps and SRE standards to ensure reliability and operational excellence in production environments. 🗂️ Requirements: 8+ years of experience delivering production-grade software solutions, Strong proficiency in Python, Experience with Kubernetes and containerized environments, Experience with distributed systems, Knowledge of REST and gRPC service development, Experience with cloud-native architectures, Hands-on experience with Infrastructure as Code tools, Familiarity with AI tooling and LLM-based applications, Ability to support production systems and incident response 📃 Skills: Python, Kubernetes, Docker, REST, gRPC, Terraform, CI/CD, LLM, AI, DevOps, SRE, Cloud, Automation 🏢 Description: We are looking for a Senior Platform Engineer to help build and evolve the core technology platforms that support our engineering organization. This role focuses on developing scalable software solutions, improving developer experience, and driving cloud-native engineering practices across the business. Working closely with engineering, cloud, and operations teams, you will contribute to platform architecture, automation initiatives, and the adoption of modern development and reliability practices. Key Responsibilities • Design and maintain shared platform services and engineering tools used across multiple teams. • Develop and enhance internal platforms, including authentication, developer tooling, and infrastructure services. • Build AI-powered solutions leveraging LLMs, intelligent agents, and automation technologies. • Contribute to engineering standards, architectural guidelines, and reusable frameworks. • Improve software delivery through CI/CD, automation, and Infrastructure as Code. • Promote DevOps and SRE practices, including observability, monitoring, and operational excellence. • Support production systems through incident response and reliability improvements. Required Qualifications • 8+ years of experience delivering software solutions in production environments. • Strong programming skills in Python; experience in other languages like Java, C#, C++, Go or others, nice to have • Experience with Kubernetes, containers, and distributed systems. • Knowledge of REST and gRPC service development. • Experience with solution architecture and cloud-native technologies. • Familiarity with AI tooling, agent-based frameworks, and LLM-powered applications. • Hands-on experience with Infrastructure as Code tools such as Terraform. • Strong communication and technical documentation skills.

🏢 Summary: Senior Backend Engineer role focused on designing and developing scalable, reliable backend services using Java. The position involves working in a cross-functional team to build high-performance systems, improve architecture, and support CI/CD and production environments. 🗂️ Requirements: 5+ years Backend Engineering experience, Strong Java proficiency, Solid knowledge of databases and SQL, Experience with RESTful APIs, Experience with microservices architecture, Experience with high-load systems, Experience with Docker and Kubernetes, Experience with AWS or GCP, Knowledge of CI/CD pipelines, Understanding of Agile practices 📃 Skills: Java, SQL, REST, Microservices, Docker, Kubernetes, AWS, GCP, CI/CD, Golang, Python 🏢 Description: We are looking for a Senior Backend Engineer with strong Java experience to help us design and develop scalable solutions. You will work in a cross-functional team, building reliable services and contributing to the continuous improvement of our systems. This role is ideal for someone who enjoys solving complex problems and driving technical excellence. 💼 Responsibilities: Design, develop, and maintain backend features and services. Collaborate with teams to define requirements and integrate systems. Ensure performance, scalability, and reliability of applications. Contribute to CI/CD processes and support production systems. Write clear documentation and share knowledge within the team. ✅ Requirements: 5+ years of experience as a Backend Engineer, with strong Java skills (Golang/Python is a plus). Solid understanding of databases and SQL. Experience with RESTful API design, microservices, and high-load systems. Familiarity with Docker, Kubernetes, and cloud environments (AWS/GCP). Knowledge of CI/CD pipelines and Agile practices. Strong problem-solving and communication skills. 🎁 We offer: Stable employment in a fast-growing company. Flexible and remote-friendly working model. Health and wellbeing benefits. Learning and development opportunities. Modern equipment and comfortable work environment.

🏢 Summary: Senior Software Engineer role focused on designing and developing scalable backend and fullstack applications using modern C++ in Linux environments. The position involves performance optimization, concurrency, and cloud-native technologies while contributing to high-impact product features. It requires strong ownership, collaboration, and the ability to work across diverse technologies including cloud and DevOps tools. 🗂️ Requirements: 6+ years of C++ development experience, Strong knowledge of multithreading, Strong knowledge of memory management, Experience with performance optimization, Experience developing backend systems, Experience with REST APIs, Experience working in Linux environments, Ability to design and maintain scalable systems, Bachelor’s degree in STEM field 📃 Skills: C++, Linux, REST, Multithreading, AWS, Python, Go, Terraform, CloudFormation, GitHub, Jenkins, Artifactory, Ansible 🏢 Description: Senior Software Engineer – C++ We are looking for a talented Senior Software Engineer to join our team. This role is ideal for someone with deep experience in C++ development , backend skills, and exposure to cloud-native technologies. You will work on challenging projects, contribute to high-impact features, and help shape the future of our products. What You’ll Do Design, develop, and maintain scalable backend systems in C++ (modern C++ preferred) Work on fullstack applications , including REST API-based backend services Optimize software for performance, concurrency, and memory efficiency Develop and maintain applications in Linux environments Take ownership of technical tasks, delivering high-quality results independently Collaborate closely with cross-functional teams, contributing to design and technical discussions Explore new technologies and expand beyond your primary stack, including Python, Go, and AWS Apply a product-focused mindset, understanding the business impact of your technical decisions What We’re Looking For 6+ years of hands-on experience in C++ development Solid understanding of multithreading, memory management, and performance optimization Strong experience contributing to complex features with exposure to diverse technologies Proven ability to work effectively in a team and communicate clearly Experience with Linux-based systems and development in Linux environments Self-motivated, independent, and capable of delivering results with limited supervision Bachelor’s degree in Science, Technology, Engineering, or a related field Nice to Have Experience with Go and/or Python Knowledge of cloud-native development and Infrastructure-as-Code tools (Terraform, CloudFormation) Background in enterprise-scale applications or AWS serverless architectures Familiarity with networking protocols, security best practices, and database systems Experience with modern CI/CD pipelines (GitHub, Jenkins, Artifactory, Ansible)

🏢 Summary: Senior Backend Engineer role focused on building and maintaining scalable backend systems using NodeJs, Python, MongoDB, MQTT, and AWS. The position involves full lifecycle development, API and system design, code quality improvements, mentoring junior engineers, and contributing to technical strategy. Candidates should have strong backend engineering experience, testing knowledge, and familiarity with CI/CD and monitoring practices. 🗂️ Requirements: 4+ years of professional experience with NodeJs, 4+ years of professional experience with Python, 4+ years of professional experience with MongoDB, 4+ years of professional experience with MQTT, 4+ years of professional experience with AWS, Backend development experience, Experience building web applications and APIs, Ability to write clean, maintainable code, Knowledge of SOLID principles, Experience with testing strategies and implementations, System design experience from ambiguous requirements, Understanding of CI/CD practices, Experience with logging and monitoring tools, Knowledge of version control best practices 📃 Skills: NodeJs, Python, MongoDB, MQTT, AWS, Go, APIs, CI/CD, SOLID, Git, Testing, Monitoring, Logging 🏢 Description: Introduction & Summary: We are seeking an experienced Senior Backend Engineer who will be responsible for building and maintaining robust backend systems. The ideal candidate will possess a strong background in backend development, particularly with NodeJs, Python, MongoDB, MQTT, and AWS. A proactive problem-solver with a focus on clean, maintainable code and system design will thrive in this role. Main Responsibilities: Participate in all stages of the development and post-development lifecycle Proactively provide creative, thorough, and practical solutions to technical problems Design, write, and maintain well-organized, scalable, and testable code Identify and address issues and bottlenecks, advocating for changes Promote best practices and code quality within the team Contribute to refining technical vision and aligning it with business objectives Mentor and guide junior engineers Key Requirements: Hands-on experience in backend development and engineering At least 4 years of professional experience with NodeJs, Python, MongoDB, MQTT, and AWS Experience with GO is advantageous Proven experience in building web applications and APIs Ability to write clean, maintainable code and apply SOLID principles Experience with various testing strategies and implementations Capability to design systems from ambiguous product requirements Understanding of continuous integration and delivery Proficiency with logging and monitoring tools Knowledge of version control best practices Proactive mindset emphasizing continuous improvement and learning Nice to Have: Strong problem-solving skills and critical thinking regarding technical challenges Flexibility and willingness to adapt to changing priorities and technologies Other Details: This role offers a dynamic work environment with opportunities for growth and development. Ideal candidates will commit to excellence and a proactive approach in their work.

🏢 Summary: Senior Software Engineer role focused on designing and delivering scalable solutions within complex distributed systems at significant scale. The position requires strong ownership, architectural decision-making, and collaboration across cross-functional teams. The engineer will drive high-impact technical initiatives in a large, distributed environment. 🗂️ Requirements: Degree in Computer Science or equivalent practical experience, Proven experience delivering complex, large-scale software solutions, Hands-on experience with distributed systems, Ability to make independent architectural decisions, Strong collaboration and communication skills, Ability to operate autonomously with high ownership 📃 Skills: DistributedSystems, Architecture, Scalability, Reliability, Observability, SoftwareEngineering, ComputerScience 🏢 Description: Senior Software Engineer About the Role We are looking for a Senior Software Engineer to join a high-scale product environment operating within complex distributed systems. This role is designed for a highly autonomous individual contributor who can take ownership of complex technical initiatives, influence architectural direction, and deliver scalable, reliable solutions in a large organizational setting. You will collaborate cross-functionally with engineering, product, and design teams while contributing to systems used at significant scale. Key Responsibilities Design and deliver high-complexity system components and features Make informed architectural decisions and evaluate technical trade-offs Ensure quality, scalability, reliability, and observability of delivered solutions Identify and manage technical risks, dependencies, and technical debt Develop deep understanding of the product domain and user impact Collaborate effectively across teams in a distributed engineering environment Operate with high autonomy and ownership Contribute to or elevate engineering standards within the team Mentor or support less experienced engineers when needed Requirements Education Degree in Computer Science, Software Engineering, or equivalent practical experience Experience & Competencies Proven experience as a Senior Software Engineer delivering complex, large-scale solutions Hands-on experience working with distributed systems Strong communication and collaboration skills Ability to independently drive architectural decisions Strong sense of ownership over delivered solutions Nice to Have Experience shaping or improving team-level engineering standards Experience collaborating across multiple teams in complex organizational structures

🏢 Summary: The offer is for a Software Engineer to modernize and develop cloud-hosted backend services for a mission-critical aviation platform used globally. The role focuses on building scalable, resilient, cloud-native solutions in AWS, improving automation, CI/CD, and Kubernetes-based environments. You will contribute to transforming a legacy system into a modern, secure, and highly scalable ecosystem. 🗂️ Requirements: Experience developing backend applications in cloud environments, Hands-on experience with Linux, Docker, Apache, PHP, Strong knowledge of AWS and cloud-native architectures, Experience with Kubernetes and containerized workloads, Experience with CI/CD and Infrastructure as Code, Knowledge of cloud security and monitoring practices, Ability to troubleshoot production systems, English B2 level or higher 📃 Skills: AWS, Linux, Docker, Apache, PHP, Kubernetes, CI/CD, IaC, SQL, MySQL, SQLServer, AI 🏢 Description: We are looking for a Software Engineer to join a team responsible for modernizing a mission-critical aviation platform used by tens of thousands of customers worldwide. You will help design, build, and evolve cloud-hosted backend services that support the distribution of aviation data across desktop, mobile, and aircraft-connected workflows. This is a unique opportunity to work on a high-impact product while contributing to a large-scale modernization initiative focused on cloud-native architecture, automation, scalability, security, and operational excellence. Working closely with cross-functional teams, you will help transform a well-established platform into a modern, resilient, and highly scalable ecosystem capable of supporting future growth and new product offerings. Key responsibilities Develop and modernize backend services hosted in AWS Design and implement scalable, resilient cloud-native solutions Build and improve APIs, integrations, and automated backend processes Enhance CI/CD pipelines, infrastructure automation, monitoring, and observability Manage and troubleshoot Kubernetes-based environments and containerized applications Support production systems and drive reliability, security, and operational improvements Collaborate with product, mobile, desktop, QA, and DevOps teams to deliver high-quality solutions Leverage AI-assisted development tools to improve engineering efficiency while maintaining high standards of quality and security Ideal candidate profile Experience developing backend applications in cloud environments Hands-on experience with Linux, Docker, Apache, and PHP or Java Strong knowledge of AWS and cloud-native architectures Experience with Kubernetes and containerized workloads Experience with CI/CD, Infrastructure as Code, and automation Understanding of cloud security, monitoring, and production support practices Strong troubleshooting and problem-solving skills Ability to work independently and collaborate within distributed teams English min. B2. Nice to Have: Experience modernizing legacy applications and services Experience with SQL Server and MySQL Experience building highly available and resilient production systems Experience using AI-assisted software development tools Conditions Employment type: B2B or UoP Location: Gdańsk Work model: 1 day a week in the office in Gdańsk or less frequently, depending on your availability Salary: up to 190 PLN net/h Benefits: life insurance, private healthcare, Multisport card Recruitment steps Recruitment call with Agnieszka from KUBO Client interview (may require 2 rounds) Feedback and decision

🏢 Summary: Opportunity to modernize a mission-critical aviation platform by designing and developing cloud-hosted backend services in a scalable, cloud-native AWS environment. The role focuses on building resilient APIs, improving automation and CI/CD pipelines, and managing Kubernetes-based infrastructure to support global aviation data distribution. You will contribute to a large-scale modernization initiative emphasizing scalability, security, and operational excellence. 🗂️ Requirements: Experience developing backend applications in cloud environments, Hands-on experience with Linux, Docker, Apache, and PHP or Java, Strong knowledge of AWS and cloud-native architectures, Experience with Kubernetes and containerized workloads, Experience with CI/CD and Infrastructure as Code, Understanding of cloud security, monitoring, and production support practices, Strong troubleshooting and problem-solving skills, English proficiency at minimum B2 level 📃 Skills: AWS, Linux, Docker, Apache, PHP, Java, Kubernetes, CI/CD, IaC, SQL, SQLServer, MySQL, AI 🏢 Description: We are looking for a Software Engineer to join a team responsible for modernizing a mission-critical aviation platform used by tens of thousands of customers worldwide. You will help design, build, and evolve cloud-hosted backend services that support the distribution of aviation data across desktop, mobile, and aircraft-connected workflows. This is a unique opportunity to work on a high-impact product while contributing to a large-scale modernization initiative focused on cloud-native architecture, automation, scalability, security, and operational excellence. Working closely with cross-functional teams, you will help transform a well-established platform into a modern, resilient, and highly scalable ecosystem capable of supporting future growth and new product offerings. Key responsibilities Develop and modernize backend services hosted in AWS Design and implement scalable, resilient cloud-native solutions Build and improve APIs, integrations, and automated backend processes Enhance CI/CD pipelines, infrastructure automation, monitoring, and observability Manage and troubleshoot Kubernetes-based environments and containerized applications Support production systems and drive reliability, security, and operational improvements Collaborate with product, mobile, desktop, QA, and DevOps teams to deliver high-quality solutions Leverage AI-assisted development tools to improve engineering efficiency while maintaining high standards of quality and security Ideal candidate profile Experience developing backend applications in cloud environments Hands-on experience with Linux, Docker, Apache, and PHP or Java Strong knowledge of AWS and cloud-native architectures Experience with Kubernetes and containerized workloads Experience with CI/CD, Infrastructure as Code, and automation Understanding of cloud security, monitoring, and production support practices Strong troubleshooting and problem-solving skills Ability to work independently and collaborate within distributed teams English min. B2. Nice to Have: Experience modernizing legacy applications and services Experience with SQL Server and MySQL Experience building highly available and resilient production systems Experience using AI-assisted software development tools Conditions Employment type: B2B or UoP Location: Gdańsk Work model: 1 day a week in the office in Gdańsk or less frequently, depending on your availability Salary: up to 190 PLN net/h Benefits: life insurance, private healthcare, Multisport card Recruitment steps Recruitment call with Agnieszka from KUBO Client interview (may require 2 rounds) Feedback and decision