Senior Software Engineer - Blockchain

As a Senior Software Engineer - Blockchain at Mastercard, you join the Mastercard Blockchain and Digital Assets Engineering team to design, develop, and deliver high-performance Ethereum/EVM and Web3 solutions for global markets. You'll work in a highly collaborative Agile team building innovative, scalable products with a strong focus on enterprise-grade architecture, scalability, security, and reliability. The team focuses on adopting blockchain technology to bring innovative payment solutions to market and has opportunities to work alongside cutting-edge AI tools and agentic systems.

What you'll do

• Design and develop scalable, production-grade smart contract systems and Web3 integrations within the Ethereum/EVM ecosystem
• Lead technical design and architecture discussions, making sound engineering decisions while balancing scalability, security, performance, and maintainability
• Translate complex business requirements into robust blockchain-based solutions aligned with enterprise standards and best practices
• Participate in architecture reviews, code reviews, and technical design sessions to drive engineering excellence
• Collaborate with product, compliance, security, and engineering teams throughout the software development lifecycle
• Mentor and support engineers by sharing knowledge, promoting best practices, and fostering technical growth across the team
• Evaluate emerging blockchain technologies, protocols, development frameworks, and industry trends to identify new opportunities and improvements
• Contribute to the continuous evolution of engineering practices, tooling, automation, and software quality standards
• Develop, test, deploy, and support applications and services in cloud-native, containerized environments
• Champion secure coding practices and operational excellence across all phases of development and delivery

What you bring

• Proven experience as a Software Engineer, Software Developer, or similar engineering role
• Strong expertise in Ethereum/EVM and Web3 development using frameworks such as ethers.js, web3.js, or equivalent technologies
• Proficiency in Solidity with hands-on experience designing, developing, and deploying production-grade smart contracts
• Deep understanding of blockchain fundamentals, including consensus mechanisms, transaction lifecycle, gas optimization, wallet infrastructure, and security best practices
• Experience with smart contract development frameworks such as Hardhat, Foundry, or similar toolchains
• Strong knowledge of software engineering principles, system design, and modern development methodologies
• Experience working with containerization and orchestration technologies such as Docker and Kubernetes
• Familiarity with CI/CD pipelines and tools such as Jenkins or equivalent automation platforms
• Proficiency with source control systems and collaborative development practices in multi-engineer environments
• Experience building and maintaining automated unit, integration, and end-to-end testing solutions
• Ability to make sound technical decisions, lead initiatives, and mentor engineers through influence rather than formal authority
• Comfortable working autonomously in fast-paced Agile environments while balancing competing priorities
• Strong commitment to code quality, maintainability, security, and continuous improvement
• Strong communication and collaboration skills, with the ability to explain technical concepts and influence decisions across technical and non-technical audiences
• Bachelor's degree in Computer Science, Engineering, Information Systems, or equivalent practical experience

Nice to have

• Experience with enterprise blockchain protocols such as Hyperledger Besu, Quorum, or Canton
• Familiarity with Layer 2 scaling solutions, including Polygon, Arbitrum, or Optimism
• Knowledge of smart contract security, common vulnerability patterns, and audit processes
• Familiarity with non-EVM blockchain ecosystems, such as Solana
• Proficiency in Java or another object-oriented backend programming language
• Experience with Spring or Spring Boot
• Familiarity with TypeScript and frontend frameworks such as React or Angular
• Experience with AI and agentic engineering, including LLM integration, AI-powered developer tools, or autonomous agent frameworks

What we offer

• Competitive base salary, with variation depending on location, job-related knowledge, skills, and experience
• Annual bonus or commissions depending on the role
• Insurance including medical, prescription drug, dental, vision, disability, and life insurance
• Flexible spending account and health savings account
• Paid leaves including 16 weeks of new parent leave and up to 20 days of bereavement leave
• 80 hours of Paid Sick and Safe Time, 25 days of vacation time, and 5 personal days, pro-rated based on date of hire
• 10 annual paid U.S. observed holidays
• 401k with a best-in-class company match
• Deferred compensation for eligible roles
• Fitness reimbursement or on-site fitness facilities
• Eligibility for tuition reimbursement

About Mastercard

Mastercard powers economies and empowers people in 200+ countries and territories worldwide. The company supports a wide range of digital payments choices, building secure, simple, smart, and accessible transaction infrastructure while helping customers realise their greatest potential through innovative blockchain and digital asset solutions.