Staff Software Engineer, Web Application Services

Remote · 10+ years experience · Remote · Posted Sep 27, 2026

At a glance

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.

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.

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.
Applicants must reside in and have permanent work authorization for the country location(s) specified in the posting.

Fully remote position with schedule flexibility.
Collaborate across time zones and disciplines with a distributed team of staff, open-source community members, and contributors.
Ability and willingness to travel periodically, including internationally.