Ciklum is looking for a Senior JavaScript Engineer to join our team full-time in Ukraine. We are a custom product engineering company that supports both multinational organizations and scaling startups to solve their most complex business challenges. With a global team of over 4,000 highly skilled developers, consultants, analysts and product owners, we engineer technology that redefines industries and shapes the way people live. About the role: As a Senior JavaScript Engineer become a part of a cross-functional development team engineering experiences of tomorrow. The client is the global financial platform that removes friction from doing business across borders, with a mission to connect the world’s underserved businesses to a rising global economy. We’re a community with over 2,500 colleagues all over the world, working to serve customers, and partners in over 190 markets. By taking the complexity out of the financial workflows–including everything from global payments and compliance, to multi-currency and workforce management, to providing working capital and business intelligence–we give businesses the tools they need to work efficiently worldwide and grow with confidence. You will be a core member of the Debit Cards engineering team, a high-impact unit responsible for the full card lifecycle, from ordering and issuing to limiting, managing, and monitoring card transactions. The team integrates with 3rd party payment processors, 3D Secure systems, and MasterCard, ensuring seamless, secure, and high-performance card operations for our customers. You will lead technical initiatives across card systems, designing, building, and validating robust backend solutions that scale with business needs. You will work closely with architects, security, product, and operations teams to modernize the existing card systems into a new event-driven architecture and introduce cloud-native patterns. Build it from scratch while ensuring that card business services remain reliable, secure, and performant. Responsibilities: You are a Senior Backend Engineer with a strong sense of ownership and accountability. You are comfortable operating in fast-moving, complex environments and excel at turning ambiguity into concrete, executable solutions You bring deep backend, cloud, and architectural expertise, balancing long-term thinking with pragmatic delivery You embrace change and learn quickly, continuously adapting to new technologies, architectures, and organizational needs. You are curious by nature, proactive in closing knowledge gaps, and comfortable making informed decisions even when not all answers are known yet You thrive in cross-team environments, earning trust through technical excellence and clear communication. You influence design, implementation, and example rather than authority, and enjoy collaborating closely with product, architecture, security, and infrastructure teams to ensure alignment, adoption, and lasting impact You are impact-driven, not territory-driven, measuring success by how effectively you enable other teams and improve the organization’s cloud capabilities as a whole Requirements: 5+ years of experience with backend development, preferably Node.js - Must Previous or current experience with C# and/or Nest.js – Great Advantage 5+ years of experience with advanced SQL (MSSQL/MySQL/PostgreSQL, etc.) 3+ years of experience with NoSQL database, preferably MongoDB Experience with building SaaS platforms for cloud-based products, preferably AWS Experience with Containers and Kubernetes (K8s), preferably EKS Experience with Event-Driven Architecture Experience with Message Brokers such as RabbitMQ/SQS/Kafka, preferably Kafka - Must Experience with Microservices development Experience with AI tools for leveraging team velocity and quality - Must What`s in it for you? Strong community: Work alongside top professionals in a friendly, open-door environment Growth focus: Take on large-scale projects with a global impact and expand your expertise Tailored learning: Boost your skills with internal events (meetups, conferences, workshops), Udemy access, language courses, and company-paid certifications Endless opportunities: Explore diverse domains through internal mobility, finding the best fit to gain hands-on experience with cutting-edge technologies Flexibility: Enjoy radical flexibility – work remotely or from an office, your choice Care: We’ve got you covered with company-paid medical insurance, mental health support, and financial & legal consultations About us: At Ciklum, we are always exploring innovations, empowering each other to achieve more, and engineering solutions that matter. With us, you’ll work with cutting-edge technologies, contribute to impactful projects, and be part of a One Team culture that values collaboration and progress. As one of Ukraine’s largest IT companies and a top employer recognized by Forbes, we’ve spent over 20 years delivering meaningful tech solutions. We proudly support diverse talent and military veterans, recognizing their unique skills and perspectives they bring to shaping the future. Explore, empower, engineer with Ciklum! Interested already? We would love to get to know you! Submit your application. We can’t wait to see you at Ciklum. #LI-MG1