Senior Software Engineer (GR110-DV)

OKTO PAYMENTS' continuous growth demands high-caliber candidates who embody professionalism, passion, and creativity. For those who join us, we offer significant career advancement, stimulating challenges, and a clear runway for growth.

OKTO PAYMENTS is the next-generation Payment Service Provider - AI-native, precision-engineered, and relentlessly merchant-obsessed. Built for merchants operating in the most complex and demanding eCommerce sectors, our platform goes far beyond transaction processing. We solve for scale, compliance, and performance with one unshakable focus: delivering outcomes that power merchant growth.

From payments and banking to treasury and settlement, we engineer the financial infrastructure that gives our partners a competitive edge. The result? Faster onboarding, smarter operations, and resilient, real-time performance.

At OKTO PAYMENTS, we enable merchants to Play Differently, transforming payments from routine transactions into true differentiators that deliver personalized, frictionless experiences.

Our AI-native innovation harnesses data and insight to power every decision, while our proprietary in-house engineering ensures precision and control. Combined with deep, trust-based relationships worldwide, we’re redefining what it means to build, scale, and win in complex digital commerce.

Summary As a Senior Software Engineer, you will play a key technical leadership role in architecting, designing, and developing our next-generation payment platform. This position requires deep expertise in distributed systems, Java-based microservices, and high-volume transaction processing. You will be responsible for ensuring the platform meets the highest standards of scalability, security, and reliability while working closely with product, infrastructure, and security teams.

This position offers tremendous career growth and the opportunity to make a direct impact in a rapidly expanding international company.

Your responsibilities will include:

• Leading the design and architecture of complex distributed systems that handle real-time financial transactions at scale.
• Spearheading the integration of payment gateways, banks, card networks, and alternative payment methods.
• Taking a lead role in our transition to a microservices-based architecture for payments.
• Creating and maintaining high-quality, optimized code with robust unit tests and appropriate test coverage.
• Providing technical leadership, mentoring junior developers, and guiding the team in best practices and efficient coding techniques.
• Collaborating with cross-functional teams to deliver highly scalable, performant solutions.
• Driving continuous improvement initiatives, identifying bottlenecks, and optimizing the software development lifecycle.
• Collaborating with DevOps to optimize CI/CD pipelines, and monitoring strategies for production systems.

Requirements

• Excellent academic background: Bachelor’s or Master’s degree in Computer Engineering or a related field.
• Proven experience (7+ years) in backend software development, with at least 3 years leading teams and architecting payment systems.
• Strong understanding of payment flows, settlement, reconciliation, and fraud detection mechanisms.

Deep knowledge of Java 11+, Spring Boot.

• Strong experience with AWS cloud services, including IAM, EC2, S3, Lambda, RDS, DynamoDB, and API Gateway.
• Hands-on experience with transaction management, database tuning (PostgreSQL, MySQL, or NoSQL stores), and high-availability strategies.
• Extensive experience with Event-Driven Software Design Patterns and complex systems architecture.
• Expertise in microservices architecture, specifically with Java 11+, Spring Boot, Spring Cloud (Netflix OSS), OAuth2 Security, and JPA ORM.
• Expertise in designing secure RESTful APIs and working with OAuth2, JWT, and SSO mechanisms.
• Advanced proficiency in Git for source control and versioning.
• Strong technical writing skills, with the ability to produce clear and concise technical requirements, design documents, and specifications.
• A proven ability to communicate complex technical concepts effectively in both Greek and English.

Benefits

• 💰 Competitive Compensation
• 💻 Modern Equipment
• 📈 Career Growth
• 🎓 Continuous Learning
• 🌱 Inclusive Environment
• 🏠 Work-from-home
• 🎂 Birthday leave