Senior Back-End Engineer Blockchain

We are looking for a highly skilled and experienced Senior Back-End Engineer specializing in Blockchain technology to join our dynamic and innovative team at Mollie. As a Senior Back-End Engineer, you will play a crucial role in designing, developing, and maintaining scalable and secure blockchain-based solutions. You will work closely with cross-functional teams to integrate blockchain technology into our existing payment platform, ensuring high performance, reliability, and security. We are looking for someone who likes to be proactive in finding new ways of working and improving our current way of working to expand our services. If you have a passion for blockchain, a strong background in back-end development, and a desire to contribute to the future of online payments, we encourage you to apply. What you'll be doing:

• Design, develop, and implement robust, scalable, and secure blockchain solutions using technologies like Ethereum L2s, and Solidity.

• Collaborate with product managers, front-end engineers, and other stakeholders to define technical requirements and translate them into actionable development plans.

• Develop and maintain back-end services, APIs, and microservices that interact with blockchain networks.

• Integrate blockchain technology with existing payment systems and third-party services.

• Ensure the security, integrity, and privacy of blockchain transactions and data.

• Conduct code reviews, provide constructive feedback, and mentor junior engineers.

• Research and evaluate new blockchain technologies, protocols, and best practices to drive innovation.

• Participate in the entire software development life cycle, from conceptualization to deployment and maintenance.

• Troubleshoot and debug complex technical issues, ensuring optimal system performance.

• Work on multiple projects, in new and exciting areas for Mollie as well as on improving our current services

What you'll need:

• 5+ years of experience as a Back-End Engineer, with a strong focus on blockchain or distributed ledger technologies.

• Proficiency in at least one back-end programming language (e.g., Node.js (Typescript), Python, Go, Java, or C#). Strong preference for Typescript.

• In-depth understanding of blockchain concepts, including cryptography, consensus mechanisms, smart contracts, and decentralized applications (dApps).

• Experience with Ethereum and its ecosystem (e.g., Solidity, Web3.js, Hardhat, Truffle, Ethers.js).

• Familiarity with Layer 2 scaling solutions (e.g., Polygon, Arbitrum, Optimism) is a plus.

• Experience working with databases, both relational and NoSQL.

• Solid understanding of API design principles (RESTful, GraphQL).

• Experience with cloud platforms (e.g., AWS, Azure, Google Cloud) and containerization technologies (e.g., Docker, Kubernetes).

• Excellent problem-solving skills and the ability to work independently and collaboratively in a fast-paced environment.

• Strong communication skills, both written and verbal, with the ability to explain complex technical concepts to non-technical stakeholders.

• A keen eye for writing clean, testable, and maintainable code and following best practices.

What you'll get:

• Enjoy a competitive salary, with a high degree of autonomy

• Work in a hybrid set-up, combining working from home with working from our beautiful office in Amsterdam

• Sparkle with 25 days of annual leave, plus we'll add an extra day to celebrate your birthday!

• Invest in your personal growth with a €2,000 professional development budget every year

• Keep fit and healthy with a €300 budget to spend on your well-being

• Lunch is on us when you're in the office!

• Stay connected with our hybrid working allowance to cover your WFH costs

• Travel is on us — we’ll cover your public transport expenses

• Work with the best hardware, and to make it even better, we’ll provide you with a Home office supply budget (up to €1,400 every five years) & an internet allowance

• Look after our planet and yourself with a bicycle plan

• Boost your pension with a non-contributory pension plan

• Build your own legacy at one of Europe’s most quickly growing FinTech companies

• Referral bonus for anyone you bring to Mollie

Diversity, Equity & Inclusion

Mollie is an equal opportunity employer committed to a diverse and inclusive workplace. We explicitly encourage all qualified applicants to apply, regardless of their race, religion, gender identity or expression, sexual orientation, disability, or age. We don’t just accept diversity — we celebrate it and thrive on it for the benefit of our employees, our products, and our community. If you need any adjustments to be made during the recruitment process, please let us know.