Fullstack Software Dev Engineer II

Role details

It takes powerful technology to connect our brands and partners with an audience of hundreds of millions of people. Whether you’re looking to write mobile app code, engineer the servers behind our massive ad tech stacks, or develop algorithms to help us process trillions of data points a day, what you do here will have a huge impact on our business—and the world. About the Team Identity platforms at Yahoo provide modern, secure identity offerings for consumers and businesses interacting with Yahoo systems. These platforms operate at massive scale, serving hundreds of millions of users every day, and power critical authentication, authorization, and account management capabilities across Yahoo products. As part of Yahoo’s transition to an AI-First engineering model, teams increasingly leverage AI-assisted development environments (e.g., Cursor, Claude Code, GitHub Copilot) combined with Spec-Driven Development (SDD) workflows, to accelerate delivery while maintaining high engineering quality. About the Role We are looking for a Full Stack Software Dev Engineer II to join our Identity organization. You will work across the stack to build secure, scalable, and user-friendly authentication and account management experiences that serve hundreds of millions of users globally. In this role, you will work independently with minimal guidance, owning critical features and acting as a technical resource for your peers. A core expectation is the ability to collaborate effectively with AI systems—using structured specs, deep codebase context, and prompt modeling to guide high-quality software implementation. We seek engineers who possess an experimentation-forward mindset and view AI as a force multiplier for architectural excellence and team-wide productivity. Responsibilities Design, build, and operate secure, scalable full-stack identity systems using ReactJS, TypeScript, Java, and Node.js. Own complex features and standalone project phases end-to-end, from gathering requirements and systems design to implementation, testing, and production. Lead an AI-first development workflow within the squad, writing precise markdown specifications to drive AI-assisted code generation (Cursor, Claude Code), and taking responsibility for the rigorous validation, testing, and safety of all generated assets. Identify system bottlenecks, enhance platform reliability, and debug complex production issues in our high-traffic distributed identity systems. Proactively research and implement AI-driven efficiencies in your daily coding workflows, replacing repetitive manual tasks with structured automation, custom templates, and AI-assisted testing. Act as a technical resource for the team by sharing successful prompt engineering patterns, context modeling strategies, and workflow optimizations that level up the overall engineering velocity of the squad. Collaborate cross-functionally with Product Managers, UX Designers, Security Engineers, and other Yahoo product squads to coordinate technical integrations. Basic Qualifications Bachelor’s degree in Computer Science, a related technical field, or equivalent practical experience. 4–6 years of professional full-stack software engineering experience. Strong hands-on engineering experience using Java for robust backend services. Experience building responsive, high-performance web applications using React.js, Node.js, JavaScript/TypeScript, and modern frameworks such as Next.js. Strong core engineering fundamentals in distributed system design, API development, databases, and web security. Demonstrated experience integrating AI-assisted developer tools (e.g., Cursor, Claude Code, GitHub Copilot) into day-to-day software development workflows to build and refactor production-grade systems. Practical understanding of prompt engineering, model limitations, and structured context assembly to generate robust code outputs. Proven capability to evaluate, audit, and debug AI-generated outputs, ensuring alignment with Yahoo’s high standards for code quality, security protocols, and performance. Experience with testing frameworks, CI/CD pipelines, and writing production-ready, highly maintainable tests. Preferred Qualifications Experience building or maintaining high-scale Identity and Access Management (IAM) systems, auth protocols (OAuth, OIDC, SAML), or web security standards. Cloud platform experience (GCP, AWS, or Azure) and infrastructure-as-code. Familiarity with observability tools (Splunk, Grafana) and client/server performance profiling. Experience with structured development methodologies, such as Spec-Driven Development (SDD), API-first design, or AI-assisted diagnostic tools. Exposure to web accessibility (WCAG), internationalization, or large-scale consumer product delivery. What Success Looks Like Consistently deliver high-quality, high-impact features independently, ensuring secure user authentication experiences for hundreds of millions of users. Masterfully leverage AI-assisted tools to significantly compress development lifecycles while maintaining an ultra-high bar for security compliance and test coverage. Raise overall engineering standards by contributing to system architecture discussions, documenting clear technical specifications, and mentoring junior engineers. Accelerate squad velocity by sharing innovative, repeatable ways to integrate AI workflows into daily development, testing, and troubleshooting activities. The material job duties and responsibilities of this role include those listed above as well as adhering to Yahoo policies ; exercising sound judgment ; working effectively, safely and inclusively with others ; exhibiting trustworthiness and meeting expectations ; and safeguarding business operations and brand integrity. At Yahoo, we offer flexible hybrid work options that our employees love! While most roles don’t require regular office attendance, you may occasionally be asked to attend in-person events or team sessions. You’ll always get notice