Staff Software Engineer, Web Application Services

• Lead the technical architecture of new Services products, taking ownership of complex projects and identifying improvements that strengthen our systems as they evolve. • Write code, build prototypes and experiments, and contribute throughout the development lifecycle, from planning and testing through implementation, monitoring, and maintenance. • Help establish software patterns and make technical decisions across our Services products, including investigating and proposing technology choices. • Build and evolve analytics and infrastructure that help the team use user-generated data to inform decisions. • Take on ambiguous, high-level problems with broad scope and direct impact on Services goals, including growing users and subscribers. • Provide technical and product direction across Thunderbird and lead technical collaboration with other parts of Mozilla and community contributors when needed. • Work closely with the team and community to surface issues, refine ideas, and develop practical solutions. • Identify and plan improvements that make our systems and processes more accessible, self-serviceable, lower friction, sustainable, scalable, and easier to delegate. • Mentor other engineers through code review, documentation, technical discussions, process improvements, and ongoing guidance. • Stay current with evolving technologies, coding standards, libraries, and frameworks and apply that knowledge to your work.

Why Thunderbird? Thunderbird is one of the world’s most trusted open-source email applications, empowering more than 20 million people globally. At Thunderbird, we build privacy-respecting communication and productivity tools that help people manage their digital lives while staying in control of their data. We are open source by design. Our products are developed transparently and in collaboration with a global community of contributors, and that same spirit shapes how we work: collaboratively, inclusively, and with a shared commitment to putting users first. Our small but growing distributed team includes more than 65 people across seven countries. As Thunderbird evolves beyond a single desktop application, we are expanding across desktop, mobile, paid services, AI offerings, and enterprise-facing work to build independent, privacy-respecting alternatives to big tech ecosystems. Our revenue model combines user donations, which help keep Thunderbird’s applications freely available, with paid services that cover the costs of hosted offerings while supporting long-term sustainability and continued innovation. A note about Thunderbird and Mozilla: Thunderbird Technologies Corporation is the nonprofit-owned company behind Thunderbird email and a growing portfolio of products. While part of the Mozilla family, Thunderbird is a separate entity from Mozilla Corporation and Mozilla Foundation with its own compensation programs, benefits, and employment policies. To learn more, visit www.thunderbird.net The opportunity As a Staff Software Engineer, Services, you’ll help shape the architecture and technical direction of web-based products that extend Thunderbird beyond email. The Services team is currently focused on building offerings such as an appointment calendar and secure file storage and transfer solutions, creating valuable experiences for our users while supporting additional revenue streams for Thunderbird. This is a Staff-level individual contributor role with significant technical ownership and influence. You’ll work with designers, engineers, and community members to write code, build prototypes, solve complex problems, and make technical decisions that shape our products. You’ll take a holistic view of our code and systems, helping establish the architecture and software patterns that allow our Services products to evolve and scale. You’ll also take on broad, ambiguous problems that have a direct impact on our goals, from improving our technical architecture to helping grow Services users and subscribers. Along the way, you’ll provide technical and product direction across teams, mentor other engineers, and identify ways to make our systems and processes more sustainable, scalable, and easier to work with. What you’ll do • Lead the technical architecture of new Services products, taking ownership of complex projects and identifying improvements that strengthen our systems as they evolve. • Write code, build prototypes and experiments, and contribute throughout the development lifecycle, from planning and testing through implementation, monitoring, and maintenance. • Help establish software patterns and make technical decisions across our Services products, including investigating and proposing technology choices. • Build and evolve analytics and infrastructure that help the team use user-generated data to inform decisions. • Take on ambiguous, high-level problems with broad scope and direct impact on Services goals, including growing users and subscribers. • Provide technical and product direction across Thunderbird and lead technical collaboration with other parts of Mozilla and community contributors when needed. • Work closely with the team and community to surface issues, refine ideas, and develop practical solutions. • Identify and plan improvements that make our systems and processes more accessible, self-serviceable, lower friction, sustainable, scalable, and easier to delegate. • Mentor other engineers through code review, documentation, technical discussions, process improvements, and ongoing guidance. • Stay current with evolving technologies, coding standards, libraries, and frameworks and apply that knowledge to your work. What you bring • 10+ years of web software development experience, including experience designing scalable and efficient systems and launching complex web projects at scale. • Expert-level JavaScript skills and knowledge of at least one additional programming language, such as Python, Rust, Go, or C++. • An understanding of the business landscape, including challenges and opportunities, and experience collaborating with teams to expand Thunderbird’s user and donor base. • Experience with front-end frameworks, full-stack development, and/or API development. • Strong knowledge of software development practices, including testing, code review, and documentation, and the ability to help others develop these skills. • Experience acting as a technical lead, solving complex technical problems, and providing mentorship and guidance to other engineers. • Experience collaborating remotely across disciplines such as engineering, product management, QA, and design. • Excellent written and verbal English communication and documentation skills, with the ability to communicate clearly and concisely with an international, geographically distributed team. • Comfort working in an open-source environment and a commitment to Mozilla values. • Ability to learn, evaluate, and responsibly use emerging technologies, including AI-enabled tools, to improve work processes. • A commitment to continuous learning and staying current with industry trends and technologies. • Ability and willingness to travel periodically, including internationally. Bonus points for • Experience with product management or product-focused work. What success looks like Success in this role will look like a strong technical leader who not only helps the Web Services