Senior Backend Engineer (Kotlin / GCP / Data Platform)

🏢 Summary: Senior Backend Engineer role building and operating scalable core services and developer-facing tools for a voice platform. The position spans backend and frontend development, with end-to-end ownership of distributed, cloud-native production systems and collaboration with ML teams. 🗂️ Requirements: 6+ years building and operating distributed backend services, Professional Java experience, Experience designing gRPC/HTTP APIs, Experience with distributed systems and event-driven architectures, Experience operating cloud-native infrastructure in production, End-to-end production system ownership, Ability to collaborate with ML and cross-functional teams, Clear communication of technical trade-offs 📃 Skills: Java, Python, gRPC, HTTP, APIs, Cloud-native, Distributed, Event-driven 🏢 Description: We are looking for a Senior backend Engineer to help build the core services and user-facing tools that power a voice platform. In this role, you will develop and operate the platform's foundational backend systems while also building intuitive frontend experiences. You will work across the full stack, designing scalable backend services and creating high-quality frontend applications that enable internal teams and partners to build, test, and manage voice experiences. This is an opportunity to work on distributed systems at scale, shape developer-facing tools, and own features from concept through production. What You'll Do Design, build, and operate scalable backend services. Develop and maintain distributed systems using gRPC/HTTP APIs and event-driven architectures. Build cloud-native services with a strong focus on reliability, scalability, and performance. Own production systems end-to-end, including architecture, implementation, deployment, monitoring, and iteration. Partner closely with ML engineers to design robust interfaces between backend services and model-serving infrastructure. Collaborate with engineers and cross-functional stakeholders to deliver high-quality technical solutions. Champion engineering best practices, operational excellence, and maintainable system design. Who You Are You have 6+ years of experience building and operating distributed backend services. You have strong professional experience with Java and Python. Experience with Java is essential, while Python is a plus because much of the team's tooling is built in it. You have experience designing and developing gRPC/HTTP APIs, distributed systems, and event-driven architectures. You have experience building and operating cloud-native infrastructure in production environments. You take ownership of systems throughout their full lifecycle, from design through production support. You collaborate effectively with machine learning teams and cross-functional partners. You are an excellent communicator who can clearly explain technical trade-offs to both technical and non-technical stakeholders.

🏢 Summary: Senior Software Engineer role focused on designing, building, and operating distributed Python backend applications for customer audience management on Google Cloud. The position combines technical ownership, message-driven architecture development, production support, and collaboration on architecture and design. 🗂️ Requirements: Several years of distributed backend application development experience, Python application development capability, Software design patterns, Clean Code, SOLID principles, Relational database, SQL, and ORM experience, CI/CD and containerization experience, Message-driven architecture knowledge, Test automation experience, Agile development methodology familiarity, DevOps and production application operations experience, Cloud architecture and technology experience 📃 Skills: Python, SQL, SQLAlchemy, GitHub, Terraform, Docker, Kubernetes, GCP, BigQuery, PubSub, CloudRun, CI/CD, TDD, Scrum, Kanban 🏢 Description: As a Senior Software Engineer, you design and develop distributed back-end applications in the Google Cloud. With your products, you enable our customers to quickly and flexibly determine the appropriate target groups for coupons, newsletters and more. This means that you take responsibility for an integral part of the PAYBACK marketing platform in all four markets Germany, Austria, Poland and Italy. Your responsibilities: You assume technical responsibility in Python-based product audience management, including architecture, integration, testing, and operations. You develop and extend backend components within a message-driven architecture in the Google Cloud using established patterns and best practices. In architectural and design discussions, you bring in expertise and experience, and you promote knowledge sharing in the team. You take care of the monitoring and support of the running application as part of regular ops rotation. Your Profile: Several years of relevant experience in the design and development of distributed backend applications, preferably in Python. Readiness for application development in Python (especially if you’re coming from a different language background) Safe handling of common software development patterns (design patterns) and best practices of software development (e.g. Clean Code, SOLID Principles). Profound experience with relational databases, SQL and ORM frameworks (especially SQLAlchemy). Practical experience with CI/CD processes and tools, ideally with GitHub, Terraform (IaC) and container technologies (Docker/Kubernetes). Sound knowledge of message-driven architectures. You have mastered the use of test automation and ideally use Test Driven Development (TDD). Familiarity with agile procedures and development methods (e.g. Scrum, Kanban). Experience in DevOps practice and in operating applications in a production environment. Experience with cloud technologies and architectures, preferably Google Cloud Platform (GCP) with BigQuery, PubSub, CloudRun. How about? Employment contract?Of course. With us you do not have to worry about stable employment. Benefits?We have them! Among other: corporate incentive program, sport card, private medical care. Lunch card?With the cooperation extended and permanent contract, you will receive additional funds to use for meal purchases. Working in a hybrid model?Of course! ! You work with us 2 days a week from home. Work wherever you want?In PAYBACK you have the opportunity. Working 100% remotely, also from European countries for 15 days a year. Flexible working hours?Sounds great! We start working between 7 to 10. Trainings?Of course. We provide training to develop hard and soft skills. Convenient location?Sure! We invite you to our new office at Rondo Daszyńskiego, but we are currently also working remotely. Dress code?We definitely say no. There are no rigid dress code rules in our company, sneakers are more than welcome. Friendly atmosphere at work?Yes! In PAYBACK, people are the most important asset‎. ‎Something is missing?Open communication is our priority, so dare to ask!‎

🏢 Summary: Senior/Lead Product & Platform Engineer role to enhance a core platform using Kotlin, Java and GCP. The offer covers API, microservice and asynchronous-systems development, production reliability, AI/LLM capabilities and technical mentoring in a remote B2B engagement. 🗂️ Requirements: 5+ years of commercial Java development experience, Commercial Kotlin and Java experience, GCP experience: Cloud Run, Compute Engine, Cloud Storage, IAM, networking, REST API, microservices and distributed-systems experience, PostgreSQL, Redis and Firestore experience, CI/CD, Docker and automated-deployment experience, AI-agentic / LLM feature delivery experience, Retrieval grounding, moderation and hallucination-management knowledge, Ability to work in unfamiliar Kotlin/GCP codebases with AI coding tools, English proficiency at C1 level, Independent work, engineering judgement and mentoring ability 📃 Skills: Java, Kotlin, GCP, CloudRun, ComputeEngine, CloudStorage, IAM, REST, Microservices, PostgreSQL, Redis, Firestore, CI/CD, Docker, LLM, AI, Grounding, Moderation, Kotlin, Networking 🏢 Description: We are looking for a Senior / Lead Product & Platform Engineer to join a product development team working on a core platform focused on product enhancement, performance, reusable capabilities and complex engineering. You will work closely with an international team, contribute to the development of the platform and mentor engineers joining the project. In Short 🌎 100% REMOTELY or from one of our 2 offices 💰 170 - 200 PLN/h + VAT ☑️ B2B contract Your Daily Missions Developing and enhancing a core product platform. Working with Kotlin and Java on GCP . Building REST APIs, microservices and asynchronous processing solutions. Working with PostgreSQL, Redis and Firestore . Developing CI/CD and deployment automation using Docker. Ensuring proper testing, monitoring, logging and performance. Troubleshooting production issues. Building reusable capabilities and solutions. Using AI coding tools to accelerate development while verifying generated code. Mentoring other engineers and communicating technical decisions clearly. The Essentials We’re Seeking Minimum 5 years of commercial experience as a Java Developer. Strong commercial experience with Kotlin and Java . Strong experience with GCP , including Cloud Run, Compute Engine, Cloud Storage, IAM and networking. Strong written and spoken English (C1), with experience working in an international environment. Experience with REST APIs, microservices and distributed systems. Experience with PostgreSQL, Redis and Firestore . Experience with CI/CD, Docker and automated deployments. Practical experience delivering AI-agentic / LLM features . Understanding of retrieval grounding, moderation and hallucination management. Ability to quickly work in an unfamiliar Kotlin/GCP codebase using AI coding tools. Strong engineering judgement and a reusability mindset . Ability to work independently and mentor other engineers. Nice-to-haves Terraform, Pub/Sub, Vertex AI or OpenAI APIs . Experience with high availability, fault tolerance, high-throughput / low-latency systems, concurrency or caching. Experience with OAuth / OIDC / JWT, secrets management or encryption. Experience with voice or conversational AI . Experience in collections, contact-centre or financial services . Reasons Why You Would Enjoy Working With Us We work in the latest technologies and with international clients, and our projects are polished from < to /> - learn about some of the projects we have completed. We organize TechTalks, meet-ups and create guilds where we exchange knowledge - you can learn a lot from your teammates. We have a close-knit team and we make sure to have regular integrations - we often go out to celebrate together. You can work remotely or choose to work from our offices in Wroclaw or Bielsko-Biala. However, we count on your openness to occasionally visit the office for team meetings or client visits, or possible occasional trips to the client's headquarters. You can adjust your working hours to suit your needs, starting your day between 7:00 and 10:00 am. You can work with great specialists in their fields who also have a sense of humor and other after-hours hobbies. It is the people who create the unique atmosphere and relaxed atmosphere at CSHARK. We have a flat structure - we are not a corporation and don't want to be one 🙃. We offer bonuses for employee referrals (from 3000 PLN to 7000 PLN). We organize remote English classes and provide access to the company library. You can also become an author/author of articles published on our technical blog - https://cshark.com/blog/ .

🏢 Summary: Long-term B2B opportunity for a Senior Backend Software Engineer to develop and maintain European Commission eDelivery products. The role focuses on Java-based backend services, distributed systems, secure APIs, messaging, data performance, testing, observability, and CI/CD in a mostly remote EU-based arrangement. 🗂️ Requirements: 8+ years with Java, Jakarta EE, Spring/Spring Boot, and Hibernate, 7+ years with Maven, Gradle, and npm, 5+ years with Oracle DB, PostgreSQL, or MySQL, 5+ years with REST APIs or SOAP/WSDL web services, 5+ years with ActiveMQ, RabbitMQ, or Kafka, 5+ years with XML, XSD, XPath, WSDL, JSON, and JSON Schema, 5+ years with Git workflows, 1+ year with distributed transaction patterns and idempotency, English at B2 level or higher, Located within the EU 📃 Skills: Java, JakartaEE, Spring, SpringBoot, Hibernate, Maven, Gradle, npm, Oracle, PostgreSQL, MySQL, REST, SOAP, WSDL, ActiveMQ, RabbitMQ, Kafka, XML, XSD, XPath, JSON, Git, GitFlow, Domibus, DomiSMP, DomiSML, AS4, ebMS3, OpenAPI, mTLS, HSM, Docker, Terraform, Ansible, Python, Node.js 🏢 Description: Currently, for one of our Partners, we are looking for an experienced Senior Backend Software Engineer (m/f/n) to support a long-term eDelivery project delivered for an organization of the European Commission. Nature of tasks: eDelivery Development: Contribute to the development of eDelivery products (Domibus, DomiSMP, DomiSML, eDelivery Conformance Testing Platform) in coordination with Technical Architect(s). Backend Development & Testing: Develop and maintain services, write clean, functional, maintainable code, troubleshoot problems, write unit/integration tests, and integrate them into the CI/CD pipeline. Distributed Architecture: Design distributed transaction patterns, handle idempotency, duplicate detection, reliable message delivery (at-least-once / exactly-once), eventual consistency, and compensating transactions. Security & APIs: Implement authentication/authorization flows, mTLS, secrets management, HSM integration, threat modeling, and versioned REST/SOAP APIs with enforced contracts (OpenAPI, WSDL). Messaging & Integrations: Govern inter-service communication patterns, design message broker topologies (queues, topics, dead-letter handling), and integrate via standard protocols (AS4, ebMS3). Performance & Data Storage: Optimize for speed and scalability, profile database queries, resolve contention points (connection pools, thread starvation), and design data storage solutions (partitioning, sharding, zero-downtime migrations). Observability & Cloud: Implement structured logging, distributed tracing, metrics collection, participate in post-mortems, write technical documentation, and basic configuration of cloud services. Minimum Requirements: Backend languages and frameworks (Java, Jakarta EE, Spring/Spring Boot, Hibernate): at least 8 years . Build and dependency management tools (Maven, Gradle, npm): at least 7 years . Relational databases (Oracle DB, PostgreSQL, MySQL): at least 5 years . REST APIs and/or SOAP/WSDL web services: at least 5 years . Message brokers (ActiveMQ, RabbitMQ, Kafka): at least 5 years . Message format standards (XML, XSD, XPath, WSDL, JSON, JSON Schema): at least 5 years . Git and Git workflows (GitFlow, trunk-based development): at least 5 years . Experience with distributed transaction patterns and idempotency: at least 1 year . English: minimum B2 level . Nice to have: eDelivery Standards: Experience with core eDelivery standards and profiles: OASIS ebMS3, AS4, SMP, BDXL, ebCore PartyId, and technical standards. Security & PKI: Experience with security protocols, web application security, secure API design (TLS/SSL, mTLS, PKI, HTTPS, WS-Security, CSP, SOAP/REST, OAuth 2.0, OpenID Connect, JWT, SAML, OWASP mitigation) and secrets management tools (HashiCorp Vault, AWS Secrets Manager). Performance & Code Quality: Experience in JVM profiling, resolving thread contention/connection pool issues, Liquibase/zero-downtime database migrations, code reviews, static analysis (SonarQube), and technical debt management. Architecture & Messaging: Experience with standard integration protocols, enterprise messaging patterns, service discovery, circuit breakers, load balancing, and containerization (Docker). Tooling & Infrastructure: Experience with CI/CD pipelines (Bamboo, GitLab CI, GitHub Actions), Infrastructure-as-Code (Terraform, Ansible), and monitoring/telemetry tools (Dynatrace, Splunk, Elastic APM, OpenTelemetry). Other Skills & Domain: Experience with Python or Node.js, Java software architecture / enterprise software development certifications, working for European institutions, public administration, or large international organizations, and French language skills (B2+). Offer: Type of contract: B2B via SHIMI. Rate: 450-500 Eur/MD. Type of work: mostly remote work (the candidate must be located within the EU) — occasional travel to Brussels may be required (with at least 7 days' notice). Travel: Occasional travel to Brussels may be required. Two planned customer meetings per 12-month period (up to 2 days each) are foreseen and covered by the contractor. Additional travel may be reimbursed only if explicitly requested and approved by the customer. Duration of the collaboration: long-term.

🏢 Summary: Senior Backend Engineer role focused on building and maintaining multi-cloud Java services in a microservices, event-driven environment. The position includes test automation, production-code optimization, technical problem-solving, and support for service providers. 🗂️ Requirements: 4+ years of web development experience in similar environments, Bachelor’s degree in Computer Science, Information Security, or related technology field, Java 8, Spring, and Spring Boot expertise, Microservices and event-driven systems experience, Code and business-process documentation experience, Complex requirements and business-process analysis experience, Internal tools and reusable architecture development experience, Production code optimization and performance improvement experience, Application debugging, refactoring, and production-issue reproduction experience, JUnit and Mockito testing experience, Git experience, Commitment to code quality and ownership, Strong problem-solving and continuous-improvement approach, Upper-intermediate English 📃 Skills: Java, Spring, SpringBoot, Microservices, JUnit, Mockito, Git, AWS, ECS, SNS, SQS, RedShift 🏢 Description: ID77083 AgileEngine is an Inc. 5000 company that creates award-winning software for Fortune 500 brands and trailblazing startups across 17+ industries. We rank among the leaders in areas like application development and AI/ML, and our people-first culture has earned us multiple Best Place to Work awards. Why join us If you're looking for a place to grow, make an impact, and work with people who care, we'd love to meet you! :) About the role We are looking for a Senior Backend Engineer to develop and maintain multi-cloud platform services using Java 8 and Spring Boot , contributing to microservices architecture and event-driven systems within a small, high-ownership team. You will optimize production code, write unit and system tests using JUnit and Mockito, support complex business requirements gathering, and monitor service providers in the field. Experience in financial, accounting, or logistics software is a strong plus. What you will do Develop multi-cloud platform services as part of a small engineering team; Build and maintain automation frameworks to execute developer-written tests in private and public cloud environments; Optimize code, ensure engineering best practices are followed, and support the team in resolving technical challenges; Monitor and support service providers using the application in the field. Must haves 4+ years of experience in web development in similar environments; Bachelor’s degree in Computer Science, Information Security, or a related technology field; Strong knowledge of Java 8 , Spring , and Spring Boot ; Experience with Microservices and event-driven systems; Experience creating documentation for code and business processes; Experience gathering and navigating complex requirements and business processes; Experience developing internal tools and reusable architecture; Experience optimizing code and improving performance for production systems and applications; Experience debugging, refactoring applications, and reproducing production issues; Experience with testing frameworks including JUnit and Mockito ; Experience with Git ; Commitment to code quality and ownership of developed applications; Strong problem-solving skills with a proactive approach to continuous improvement; Upper-intermediate English level. Nice to haves Experience working with financial or accounting backends; Experience with Test-Driven Development (TDD); Experience with logistics software, delivery, transportation, route planning, or roadside assistance domains; Experience with AWS services such as ECS, SNS, SQS, and RedShift; Experience in architectural design, code reviews, and SOLID principles. The benefits of joining us Professional growth Accelerate your professional journey with mentorship, TechTalks, and personalized growth roadmaps Competitive compensation We match your ever-growing skills, talent, and contributions with competitive USD-based compensation and budgets for education, fitness, and team activities A selection of exciting projects Join projects with modern solutions development and top-tier clients that include Fortune 500 enterprises and leading product brands Flextime Tailor your schedule for an optimal work-life balance, by having the options of working from home and going to the office – whatever makes you the happiest and most productive. Meet Our Recruitment Process Asynchronous stage – An automated, self-paced track that helps us move faster and give you quicker feedback: Short online form to confirm basic requirements 30–60 minute skills assessment via Codility – a platform founded in Poland that helps us provide quicker feedback and streamline this stage of the process. 5-minute introduction video Synchronous stage – Live interviews Technical interview with our engineering team (scheduled at your convenience) Final interview with your future teammates If it’s a match — you’ll get an offer!