We are seeking a Senior Software Engineer to join the MetaMask Card Team. This role is at the forefront of bridging traditional finance with the decentralized web. You will be instrumental in building the core infrastructure and user-facing features for the MetaMask Debit Card, enabling millions of users to spend their digital assets in the real world directly from their wallet.

As a key member of this team, you will design and implement cross-platform components using React and React Native while developing robust backend services to manage card lifecycles and high-volume transaction processing. You will navigate the intersection of blockchain fundamentals and complex fintech integrations with card issuers and payment networks. If you are a builder who values clean code, security, and the challenge of onboarding the next billion participants to Web3, this role offers a high-trust, autonomous environment to grow your career.

• Design and implement high-performance frontend components for MetaMask Card interactions across mobile (React Native) and web (React) clients.
• Develop scalable backend services and APIs to manage card lifecycles, transaction processing, and real-time data feeds.
• Lead the secure integration with external Card Issuers, payment networks, and global compliance systems.
• Optimize system performance to handle high-volume transaction throughput typical of global payment platforms.
• Ensure seamless Web3 integration, connecting wallet-based digital assets to real-world debit card functionality.
• Collaborate within an agile, distributed engineering team to deliver clean, well-tested, and standardized code.
• Balance technical quality and web-based security considerations with the delivery of an intuitive user experience.
• Participate in the continuous improvement of MetaMask’s engineering culture, focusing on autonomy, trust, and inclusivity.

• 3+ years of professional experience with mobile-based technologies and building production-grade applications.
• Strong proficiency in React and React Native for cross-platform development.
• Expert knowledge of modern JavaScript (ES6+) and TypeScript.
• Familiarity with blockchain fundamentals and integrating Web3 libraries into applications.
• Solid experience working with APIs, middleware services, and distributed backend architectures.
• Proven track record of applying clean code practices, rigorous testing, and high coding standards.
• Deep understanding of web-based security, browser compatibility, and performance optimization.
• Professional fluency in English with excellent verbal and written communication skills.
• Bonus: Experience in FinTech, payment processing, or card issuing products.
• Bonus: Knowledge of DeFi protocols, digital asset management, or basic cryptography.