{"id":768610,"url":"https://alion.io/job/mastercard-senior-software-engineer-22","title":"Senior Software Engineer","company":{"id":252,"name":"Mastercard","domain":"mastercard.com","url":"https://alion.io/company/mastercard","size_band":"5000+","is_staffing_agency":false,"employer_type":"direct","is_intermediary":false,"listed_via":null,"ats_vendor":"Workday","truth_index":{"grade":"A","score":87,"open_postings":161,"ghost_share":0.019,"stale_share":0.453,"repost_share":0.062,"time_to_fill_p50_days":27,"computed_at":"2026-10-28T05:59:10Z"}},"role":"Backend","role_family":"Backend","seniority":"senior","employment_type":"full_time","work_mode":"on_site","remote_scope":null,"remote_scope_basis":null,"remote_working_hours":null,"hiring_geo_confidence":"structured","locations":["Lisbon, Portugal"],"countries":["PT"],"hiring_countries":[],"hiring_countries_total":0,"salary":null,"salary_estimate":{"min_usd":38000,"max_usd":97000,"period":"year","method":"role_seniority_country_remote_cell","sample_n":53},"experience_years_min":5,"visa_sponsorship":false,"relocation_package":false,"has_equity":false,"technologies":[{"name":"Angular","optional":false},{"name":"AWS","optional":false},{"name":"Azure","optional":false},{"name":"CI/CD","optional":false},{"name":"Docker","optional":false},{"name":"GraphQL","optional":false},{"name":"Java","optional":false},{"name":"Kubernetes","optional":false},{"name":"Rest API","optional":false},{"name":"Bitcoin","optional":true},{"name":"Ethereum","optional":true},{"name":"JavaScript","optional":true},{"name":"PKI","optional":true},{"name":"Polygon","optional":true},{"name":"Smart Contracts","optional":true},{"name":"Solana","optional":true},{"name":"TypeScript","optional":true}],"status":"live","first_seen_at":"2026-09-11T20:44:26Z","employer_posted_date":"2026-09-11","last_verified_at":"2026-10-28T09:25:50Z","board_verified":true,"closed_at":null,"days_open":46,"trust":{"level":"ok","repost_count":null,"flags":[],"days_open":46},"description":"Our Purpose\nMastercard powers economies and empowers people in 200+ countries and territories worldwide. Together with our customers, we’re helping build a sustainable economy where everyone can prosper. We support a wide range of digital payments choices, making transactions secure, simple, smart and accessible. Our technology and innovation, partnerships and networks combine to deliver a unique set of products and services that help people, businesses and governments realize their greatest potential.\nTitle and Summary\nSenior Software EngineerSenior Software Engineer, Blockchain TeamLocation: Lisbon, Portugal\nExperience: 5+ years\nEmployment Type: Full-time\nOverview\nWe are seeking a highly skilled Senior Software Engineer to join our Blockchain Team in Lisbon. In this role, you will design, develop, and maintain secure, scalable, and high-performance distributed systems that support blockchain-based products and services. You will collaborate with cross-functional teams to deliver innovative solutions while driving engineering excellence and mentoring other developers.\nKey Responsibilities\nDesign, develop, and maintain blockchain platforms and distributed applications.\nBuild secure and scalable backend services using modern software engineering practices.\nDevelop integrations with blockchain networks, digital asset platforms, and cryptographic services.\nCreate and maintain APIs, microservices, and cloud-native applications.\nParticipate in architecture discussions and influence technical direction.\nEnsure high availability, performance, security, and reliability of production systems.\nExperience with cryptographic protocols, key management, and secure data handling practices.\nConduct code reviews and mentor junior and mid-level engineers.\nCollaborate with Product Managers, Architects, Security Engineers, and Operations teams.\nDrive automation, testing, CI/CD, and operational excellence initiatives.\nTroubleshoot complex technical issues across distributed environments.\nRequired Qualifications\nBachelor's or Master's degree in Computer Science, Software Engineering, or a related field.\n5+ years of professional software engineering experience.\nStrong proficiency in Java and Spring.\nExperience developing full-stack applications, including scalable backend services and modern, responsive frontend solutions.\nStrong hands-on experience with frontend framework Angular.\nExperience building responsive, accessible, and user-friendly web applications.\nStrong understanding of REST APIs, GraphQL, and frontend-backend integration patterns.\nExperience building scalable microservices and distributed systems.\nStrong understanding of cloud platforms such as AWS or Azure.\nSolid knowledge of software design patterns, system architecture, and performance optimization.\nExperience with CI/CD pipelines, containerization, Docker, and Kubernetes.\nFamiliarity with modern testing frameworks for both frontend and backend development.\nExcellent problem-solving, communication, and collaboration skills.\nAbility to lead technical initiatives, mentor engineers, and drive best practices across the software development lifecycle.\nPreferred Qualifications\nExperience with blockchain technologies such as Ethereum, Hyperledger, Bitcoin, Polygon, Solana, or similar platforms.\nUnderstanding of cryptography, PKI, digital signatures, encryption, and secure key management.\nExperience developing user interfaces for blockchain or digital asset platforms.\nKnowledge of Web3 technologies, wallet integrations, and smart contract interactions.\nExperience with event-driven architectures, messaging systems, and real-time applications.\nExperience designing and implementing secure authentication and authorization solutions (OAuth2, OIDC, MFA).\nPrevious experience leading technical projects and mentoring engineers.\nWhat Success Looks Like\nDelivering reliable and secure blockchain solutions to production.\nImproving system scalability, maintainability, and performance.\nInfluencing architectural decisions and engineering standards.\nSupporting team growth through technical leadership and mentorship.\nDriving innovation in blockchain, security, and distributed systems technologies.\nKey Competencies\nTechnical Leadership\nDistributed Systems Design\nBlockchain Architecture\nSecure Software Development\nCloud-Native Engineering\nProblem Solving\nCollaboration and Communication\n• Mentorship and Coaching\nCorporate Security Responsibility\nAll activities involving access to Mastercard assets, information, and networks comes with an inherent risk to the organization and, therefore, it is expected that every person working for, or on behalf of, Mastercard is responsible for information security and must:\nAbide by Mastercard’s security policies and practices;\n\nEnsure the confidentiality and integrity of the information being accessed;\n\nReport any 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