Senior / Lead Java Engineer

B2B Project: Senior / Lead Java Engineer Hays Contracting Services is a cooperation based on B2B rules. We connect IT specialists with the most interesting technological projects on the market. For our client, an international technology organization delivering large-scale digital solutions for global business users, we are currently looking for experts interested in the role of Senior / Lead Java Engineer. Cooperation mode: Hybrid, Kraków (3 days per week from the client's office)Compensation: up to 136 PLN/h net (+ VAT) for Senior level | up to 156 PLN/h net (+ VAT) for Lead levelStart Date: ASAPCooperation: Initial agreement until 31.12.2026 with the possibility of continuing the project, depending on future project needsContract type: B2B, through Hays PolandLanguage: English – B2+ Project Overview: You will join an international team responsible for delivering scalable backend solutions supporting business-critical platforms used globally. The project combines modern cloud technologies, distributed systems, microservices architecture and DevOps practices. We are looking for experienced Java Engineers who enjoy solving complex technical challenges, working in cloud environments and contributing to the development of reliable, high-performance applications. For the Lead role, additional experience in coordinating engineering activities and mentoring other specialists is required. Senior Java Engineer Deliver backend solutions using modern Java technologies and microservice architectureDesign and integrate APIs supporting high-volume business processesBuild and maintain cloud-native applications deployed in Kubernetes environmentsCollaborate with international teams to ensure scalability, reliability and performance of delivered solutionsCollaborate closely with QA, SRE, Product, and other engineering teamsParticipate in CI/CD processes, deployments, and production support activitiesSupport release cycles, including smoke testing and manual validationTroubleshoot issues using logs, metrics, and monitoring solutionsParticipate in code reviews and knowledge-sharing initiatives Lead Java Engineer In addition to the above scope, the Lead role includes: As a Lead Engineer, you will play a key role in shaping technical direction, supporting architecture decisions and facilitating cooperation across engineering teams while remaining hands-on in software delivery.Supporting engineering standards and best practicesDriving technical decision-making and ensuring delivery qualitySupporting stakeholder communication within the project environment Key Requirements: Minimum 6 years of commercial experience with Java and Spring Boot (Senior)Minimum 7 years of commercial experience, including experience coordinating technical activities or teams (Lead)Strong practical experience building microservices, REST APIs, and gRPC servicesHands-on experience with Google Cloud Platform (GCP)Experience with Docker and KubernetesSolid understanding of CI/CD practicesExperience with GitHub, Jenkins, or GitHub ActionsKnowledge of monitoring solutions such as Prometheus and Cloud MonitoringBasic scripting skills using Python or BashExperience with WireMock and performance testingAbility to communicate effectively in an international project environmentEnglish at minimum B2 level Nice to Have: Experience within large-scale distributed systemsKnowledge of travel, airline, booking, or retail technology domainsExperience working with event-driven architecturesFamiliarity with reliability and observability practices in cloud-native environments What We Offer: A quick competency assessment processStandard benefits including preferential rates for LuxMed, Multisport and life insurance packagesThe chance for a long-term cooperation on projects for top players in numerous sectorsOpportunities for future assignments with other leading clients through Hays What Will the Competency Assessment Process Look Like? Your CV will be verified by a Hays RecruiterA Hays representative will contact you by phone for a short discussion about the project and your experienceProject meetings with the client conducted in Polish and EnglishDecision regarding further cooperation within the projectWelcome to the project! Hays Poland sp. z o.o. is an employment agency registered in a registry kept by Marshal of the Mazowieckie Voivodeship under the number 361.