Sr Engineering Manager, Web Apps

Why Thunderbird?

Thunderbird is one of the world’s most trusted open-source email applications, empowering more than 20 million people globally. At MZLA, the team behind Thunderbird, we build privacy-respecting communication 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 65+ people across seven countries. As Thunderbird evolves beyond a single desktop application, we are expanding across desktop, mobile, and paid services to build independent, privacy-respecting alternatives to big tech ecosystems.

Our revenue model combines user donations, which help keep Thunderbird’s apps freely available, with paid services that cover the costs of hosted offerings while supporting long-term sustainability and continued innovation.

A note about MZLA and Mozilla: MZLA Technologies Corporation is the nonprofit-owned company behind Thunderbird and part of the Mozilla family. MZLA is separate from Mozilla Corporation and has its own compensation programs, benefits, and employment policies.

To learn more, visit www.thunderbird.net

The opportunity

Thunderbird is growing beyond our free desktop and mobile applications, and we’re looking for a Senior Manager, Web Applications to lead day-to-day engineering execution and people management for the team responsible for MZLA’s hosted subscription products.

This is a critical product and revenue area for MZLA. The Senior Manager will help the team launch, maintain, and improve hosted services with strong delivery discipline, clear ownership, reliable engineering practices, and a continued focus on quality, privacy, reliability, and user trust.

This is a hands-on technical management role for someone who is comfortable staying close to the codebase, product direction, service reliability needs, release readiness, and engineering tradeoffs while also leading people and improving how the team operates. As the Web Applications team continues to mature, this role will require an engaged manager who can help create structure, solve problems, support execution, and build stronger systems around the work.

This role requires consistent overlap with EST time zone working hours, and we strongly prefer candidates located in or closely aligned with this time zone.

What you’ll do 

• Lead day-to-day engineering execution in a hands-on management capacity, ensuring priorities, ownership, timelines, risks, dependencies, and quality expectations are clear.
• Manage Web Services engineers and contractors, including coaching, feedback, prioritization, performance support, and team development.
• Manage team budget and resource planning, including contractor, vendor, tooling, service, operational expense, and headcount planning inputs.
• Translate product direction, technical priorities, and organizational needs into coordinated engineering plans.
• Establish team processes, workflows, planning practices, and operating rhythms that improve clarity, accountability, quality, and predictability.
• Maintain enough product and architectural context to evaluate tradeoffs, identify risks, and manage engineering work credibly.
• Improve engineering practices related to code review, testing, documentation, release readiness, observability, technical debt, and operational readiness.
• Coordinate launch and operational readiness across technical and cross-functional partners.
• Communicate progress, priorities, risks, and decisions clearly to stakeholders while fostering an engineering culture grounded in accountability, inclusion, technical quality, open-source values, and continuous improvement.

What you bring 

• 15+ years of overall industry experience, with at least 10 years of engineering leadership experience in software product, hosted services, SaaS, cloud-based applications, communications platforms, or similarly complex technical environments.
• 5+ years of people management experience in an engineering environment, including coaching, feedback, prioritization, performance support, career development, and team development.
• Experience managing senior technical teams, team budg