Expert JavaScript Engineer

Ciklum is looking for an Expert JavaScript Engineer to join our team full-time in the Czech Republic. 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 an Expert JavaScript Engineer, become a part of a cross-functional development team engineering experiences of tomorrow. Responsibilities: Design and implement rich frontend experiences and scalable backend services that power Fireblocks’ wallet infrastructure through the Dynamic platform Own features across the stack: from technical design and architecture through implementation, testing, deployment, and ongoing optimization Build and maintain backend services and APIs supporting authentication, wallets, and payments infrastructure Develop user-facing features and frontend tooling for both end-user and developer-facing applications Collaborate closely with Product, Design, and other engineering teams to deliver robust, high-impact features Contribute to performance, reliability, and scalability improvements across the platform Help uphold engineering best practices through code reviews, testing, documentation, and knowledge sharing Requirements: 3–5 years of experience building and shipping production-grade, full-stack web applications Experience building backend systems and APIs using Node.js (and frameworks such as Express) Comfort working across frontend and backend systems in complex, evolving codebases A strong appreciation for clean, maintainable code and system performance Experience collaborating cross-functionally with product and design partners Curiosity about fintech and Web3, and interest in building infrastructure used at global scale Desirable: Experience with blockchain technologies (e.g., EVM chains, wallets, on-chain integrations) Solidity experience – writing, deploying, testing, or interacting with smart contracts in production environments Experience maintaining, testing, and securing smart contract systems post-deployment Experience with a variety of state management solutions in production React applications Experience with security products or other high-sensitivity domains What’s in it for you? Flexible working hours Home office option 5 weeks of holiday 5 sick days Multisport Card Meal allowance Internal trainings including workshops and seminars Paid certifications and technical as well as soft-skills training Possibility to participate in international conferences Fresh fruit, coffee, and a weekly company breakfast in the office Loyalty bonus after 5, 10, 15 and more years with the company Referral bonus programme Corporate events including team building, outdoor activities, Christmas party, health week, summer ice cream, and more Hybrid and remote working options available across our Czech offices in Prague, Hradec Králové, and Zlín 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. With delivery centers in Prague, Hradec Králové, and Zlín, our Czech team delivers end-to-end solutions across industries. Here, innovation thrives through collaboration, and every idea drives our partners' success. 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-IK1