Fullstack Sr Software Dev Engineer

Yahoo serves as a trusted guide for hundreds of millions of people worldwide, helping them achieve their goals online through a portfolio of iconic products. For advertisers, Yahoo Advertising offers omnichannel solutions and powerful data to engage with our brands and deliver results.

Membership 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 daily, and power critical authentication, authorization, account management, privacy, wallet and loyalty capabilities across Yahoo products.

We are looking for a Senior Full‑Stack Software Development Engineer ready to build the next generation of secure, scalable Customer Care systems that serve hundreds of millions of users globally. As a senior professional, you possess specialized depth in full‑stack architecture and a commitment to modern, AI‑augmented engineering practices.

• Design, build, and operate high‑scale Customer Care and Identity systems using React, Type Script, and Java/Node.js with a strong focus on security and availability.
• Lead an AI‑first development workflow within the squad, utilizing precise markdown specifications to drive AI‑assisted code generation (such as Cursor and Claude Code), while taking ownership of validation, testing, and safety of all generated assets.
• Own complex full‑stack features end‑to‑end, from initial technical requirements and system design to production monitoring and operational excellence.
• Proactively identify and implement AI‑driven efficiencies in daily engineering workflows, replacing repetitive manual tasks with structured automation, custom templates, and AI‑assisted testing.
• Optimize system performance and reliability by diagnosing bottlenecks and implementing AI‑assisted performance profiling and diagnostics.
• Mentor engineers across the squad, raising engineering standards through peer reviews, detailed design sessions, and scaling modern AI‑first development best practices.
• Exercise critical technical judgment to audit, validate, and debug AI‑generated code outputs, ensuring all implementations meet Yahoo’s rigorous security and performance standards.
• Collaborate cross‑functionally with Product Managers, UX Designers, Security Engineers, and adjacent Yahoo product squads to coordinate complex technical integrations.

• Bachelor’s degree in Computer Science, a related technical field, or equivalent practical experience.
• 5‑8 years of professional full‑stack software engineering experience.
• Strong hands‑on engineering experience using Java for robust, secure backend services.
• Experience building responsive, high‑performance web applications using React.js, Node.js, JavaScript/Type Script, and modern frameworks (e.g., Next.js).
• Strong fundamentals in system design, RESTful APIs, distributed systems, and web security protocols.
• Proven expertise in prompt engineering, context modeling, and structured interaction with AI development environments to build and refactor production‑grade systems.
• Demonstrated experience integrating AI‑assisted developer tools (e.g., Cursor, Claude Code, Git Hub Copilot) into day‑to‑day software development workflows.
• Proven capability to critically evaluate, audit, and debug AI‑generated outputs, ensuring the detection of errors, hallucinations, or security vulnerabilities.
• Deep experience with testing frameworks, modern CI/CD pipelines, and maintaining high codebase standards.

• Experience building or maintaining high‑scale Identity and Access Management (IAM) systems, auth protocols (OAuth, OIDC, SAML), or web security standards.
• Experience with CRM and CMS tool integrations.
• Cloud platform experience (GCP, AWS) and infrastructure‑as‑code.
• Familiarity with observability tools (Splunk, Grafana, Data Dog) 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) and internationalization (i18n).