Principal Software Engineer - Web

Yahoo Mail is the ultimate consumer inbox with hundreds of millions of users. It's the best way to access your email and stay organized from a computer, phone or tablet. With its beautiful design and lightning fast speed, Yahoo Mail makes reading, organizing, and sending emails easier than ever.

The client experiences team develops products for Yahoo Mail on Android, iOS, and Web used by over 220 million users across 40 countries and 70 languages. Yahoo Mail continues to be one of the largest and most recognizable email services in the world. Delivering over 4.5B emails daily, and with consistently top-rated mobile apps, Yahoo Mail is a critical pillar in the company's long-term growth strategy.

You will join a team of engineers who strive to deliver our users the best consumer mail experience and are willing to meticulously refine the details to achieve this goal.

• Responsible for the definition, design, development and timely completion of major new features in current and future products
• Performing code reviews for your peers where you will be learning from and contributing to a collaborative working model
• Tackling hard engineering and user experience problems and solving them in an elegant and seamless manner
• Taking ownership of features and areas of the web application that will impact millions of users
• Working with engineering team members to explore and create interesting solutions while sharing knowledge amongst the team
• Collaborating with user experience designers, product managers, and other engineers to deliver new features, enhancements, platform improvements and bug fixes
• Collaborate with other engineers to write testable, reliable code, continuously deploying to production systems
• Growing in a culture of learning through design discussions and code reviews
• Deploy, monitor and operate large scale production systems distributed across the globe
• Recommend alternative approaches to solving complex problems and use new technology to achieve goals
• Leverage GenAI developer tools (Claude Code, Cursor, Copilot, and similar) as a core part of your daily workflow to accelerate delivery, improve code quality, and scale your impact across the codebase
• Continuously evaluate and adopt emerging AI-assisted development practices, sharing learnings and effective patterns with the team

• BS in Computer Science (or equivalent) with 8+ years' experience
• Strong foundation in Computer Science, with strong competencies in data structures, algorithms, and software design
• Deep technical knowledge of responsive design and java script frameworks such as React / Angular / Ember and Node.js
• Deep technical knowledge of web application development with strong command of browser-side client technologies including AJAX, HTML5, CSS3, Type Script and object-oriented Java script
• Expert in software development domain and principles, including design patterns, code structure, programming languages, continuous integration, and deployment architecture
• Experience with Web Technologies (Node, HTTP, JSON, Webpack)
• Experience with test driven development, unit test / UI test frameworks such as Jest / Selenium / WebdriverIO / Puppeteer / Cypress is an added advantage
• Expert knowledge of web application performance, stability and debugging
• Demonstrated proficiency using GenAI coding assistants (Claude Code, Cursor, Git Hub Copilot, or equivalent) in production development work - including effective prompting, reviewing AI-generated code critically, and knowing when to rely on these tools vs. when not to

• Experience developing mail applications
• Experience with AI, ML and GenAI (model training, RAG pipelines, agentic systems, or building AI-powered product features) ronments
• Experience with mobile web development
• Experience with Scrum, Squad, or similar agile development methodologies
• Exposure to accessibility (a11y) or internationalization (i18n) for large-scale systems

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…