React Jobs in Web3

Our Purpose

Mastercard 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.

Title And Summary

Senior Software Engineer - Blockchain

Overview

Mastercard is looking for a talented Senior Software Engineer - Blockchain to join the Mastercard Blockchain and Digital Assets Engineering team. In this role, you will be part of a highly collaborative Agile team building innovative, scalable products leveraging blockchain technologies and components for global markets.

You will work alongside talented engineers to design, develop, and deliver high-performance Ethereum/EVM and Web3 solutions, with a strong focus on enterprise-grade architecture, scalability, security, and reliability.

Our team is built on a foundation of research and development, innovation mentality, thinking through new product lines using Blockchain / Distributed ledger technology, managing new products from inception to market validation and engaging strategically with start-ups to shape the future of commerce within the digital assets space with and for our customers. At Mastercard you will help architect and lead the future of commerce globally.

This team will have a major focus on adopting Blockchain technology to bring innovative payment solutions to market. Engineers on this team will also have the opportunity to work alongside cutting-edge AI tools and agentic systems as part of our broader innovation agenda.

Role

• 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.
  
  
  

All About You

• 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 and 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.
  
  
  

Preferred Qualifications

• 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.
  
  
  

Mastercard is a merit-based, inclusive, equal opportunity employer that considers applicants without regard to gender, gender identity, sexual orientation, race, ethnicity, disabled or veteran status, or any other characteristic protected by law. We hire the most qualified candidate for the role. In the US or Canada, if you require accommodations or assistance to complete the online application process or during the recruitment process, please contact [email protected] and identify the type of accommodation or assistance you are requesting. Do not include any medical or health information in this email. The Reasonable Accommodations team will respond to your email promptly.

Corporate Security Responsibility

All 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:

• Abide by Mastercard’s security policies and practices;
• Ensure the confidentiality and integrity of the information being accessed;
• Report any suspected information security violation or breach, and
• Complete all periodic mandatory security trainings in accordance with Mastercard’s guidelines.
  
  
  

In line with Mastercard’s total compensation philosophy and assuming that the job will be performed in the US, the successful candidate will be offered a competitive base salary and may be eligible for an annual bonus or commissions depending on the role. The base salary offered may vary depending on multiple factors, including but not limited to location, job-related knowledge, skills, and experience. Mastercard benefits for full time (and certain part time) employees generally include: insurance (including medical, prescription drug, dental, vision, disability, 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; and many more. Mastercard benefits for interns generally include: 56 hours of Paid Sick and Safe Time; jury duty leave; and on-site fitness facilities in some locations.

Pay Ranges

Arlington, Virginia: $132,000 - $212,000 USD