Senior Software Engineer – Blockchain Team

About the role

Mastercard is looking for a Senior Software Engineer to join its Blockchain Team in Lisbon. You will be responsible for designing, building and maintaining secure, high‑performance distributed systems that power blockchain‑based products and services.

Key responsibilities

• Design, develop and maintain blockchain platforms and distributed applications.
• Build secure, scalable backend services using Java, Spring and modern engineering practices.
• Develop integrations with blockchain networks, digital‑asset platforms and cryptographic services.
• Create and maintain APIs, micro‑services and cloud‑native applications.
• Participate in architecture discussions and influence technical direction.
• Ensure high availability, performance, security and reliability of production systems.
• Conduct code reviews, mentor junior and mid‑level engineers.
• Drive automation, testing, CI/CD and operational‑excellence initiatives.
• Troubleshoot complex technical issues across distributed environments.

Required profile

• Bachelor’s or Master’s degree in Computer Science, Software Engineering or a related field.
• 5+ years of professional software engineering experience.
• Strong proficiency in Java and Spring.
• Experience building full‑stack applications, including responsive Angular front‑ends.
• Solid understanding of REST APIs, GraphQL and frontend‑backend integration patterns.
• Experience with cloud platforms such as AWS or Azure.
• Knowledge of software design patterns, system architecture and performance optimisation.
• Hands‑on experience with CI/CD pipelines, Docker and Kubernetes.
• Familiarity with modern testing frameworks for both front‑end and back‑end development.

Required skills

• Java
• Spring Framework
• Angular
• REST APIs
• GraphQL
• AWS or Azure
• Docker
• Kubernetes
• CI/CD pipelines
• Micro‑services architecture
• Distributed systems
• Cryptographic protocols and key management