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 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.

We are a small but growing company of 60+ people distributed across seven countries. As Thunderbird evolves beyond a single desktop application, we are expanding across desktop, mobile, paid services, and new product experiences that help people and organizations work more effectively without giving up control 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 and www.thunderbolt.io.

The opportunity

Thunderbolt is an open-source, cross-platform AI product initiative from the team behind Thunderbird. It is being built around a clear principle: people and organizations should be able to use AI while staying in control of their data, infrastructure, model choices, and long-term options. Thunderbolt is designed to support flexible deployment models, integrations with AI tools and workflows, and use cases across desktop, web, and mobile.

We are looking for a Senior Engineering Manager to lead engineering execution, people management, and operating practices for Thunderbolt as it moves from R&D incubation into a more mature product and enterprise development phase. This role will help the team define what production-ready means at this stage: stronger release discipline, clearer ownership, higher user-facing product quality, stronger engineering practices, and a more scalable operating model.

This is a hands-on technical managementrole. The Senior Engineering Manager will manage a senior engineering team, stay closely engaged with the codebase and technical execution, coordinate work across employees, contractors, and technical partners, and help the team deliver a reliable, enterprise-ready open-source AI product. The right person will bring strong people management skills, strong product engineering judgment, and enough technical depth to evaluate engineering work credibly, support architectural and implementation tradeoffs, and help the team keep shipping with quality.

What you’ll do

• Lead engineering execution by clarifying priorities, ownership, timelines, risks, dependencies, and quality expectations.
• Manage engineers and contractors, including coaching, feedback, prioritization, performance support, and team development.
• Stay close to the codebase by contributing code, reviewing technical work, evaluating tradeoffs, and helping the team maintain momentum and quality.
• Partner with technical and product leadership to turn product direction, AI strategy, user experience goals, and technical priorities into coordinated engineering plans.
• Establish planning, review, release, and follow-through practices that improve predictability and reduce bottlenecks.
• Maintain high standards for code quality, testing, documentation, reliability, security awareness, maintainability, and release readiness.
• Build strong product and architectural context across AI-enabled workflows, integrations, local-first or customer-controlled architectures, and release requirements.
• Partner across product, design, enterprise-facing teams, and technical leadership to balance speed, user experience, privacy, quality, enterprise readiness, and long-term sustainability.
• Lead hiring, onboarding, and resource planning as the Thunderbolt engineering team grows.
• Help Thunderbolt scale from an incubation-stage product into a reliable, enterprise-ready open-source AI product.

What you bring

• 15+ years of professional software development experience, including significant experience in senior engineering leadership or complex product delivery roles.
• 5+ years of experience managing technical teams, including senior engineers or senior individual contributors.
• A track record of leading a team that shipped polished, top-tier products held to a genuine standard of craft.
• Strong ability to translate ambiguous product and technical direction into clear plans, ownership models, and delivery momentum.
• Technical fluency with AI-enabled products, including the ability to evaluate tradeoffs across areas such as LLM applications, RAG workflows, agents, enterprise search, automation, on-device AI, or AI evaluation.
• Demonstrated experience delivering complex applications across multiple platforms, such as desktop, web, and mobile, using technologies such as Tauri, Electron, React Native, or comparable frameworks.
• Experience with enterprise software, regulated environments, or similarly complex technical products, including security, privacy, compliance readiness, administration, integrations, and customer-controlled deployment models.
• Practical experience with local-first, offline-capable, self-hosted, hybrid, on-premise, air-gapped, or other customer-controlled product architectures, including tradeoffs related to data storage, sync, privacy, reliability, and user experience.
• Experience improving engineering practices related to technical planning, code review, release readiness, testing, documentation, CI/CD, maintainability, or technical debt management.
• Excellent communication skills around technical prioritization, release risk, ownership, quality expectations, and tradeoffs.

Bonus points for

• Experience working in open-source or maintainer-style engineering environments.
• Experience with compliance or security standards such as SOC 2, HIPAA, ISO 27001, or similar frameworks.
• Experience helping take a product from zero to one in a startup or new product initiative.

What success looks like

Success in this role means helping Thunderbolt make the leap from promising R&D-stage product to a production-ready, enterprise-grade open-source AI product that security-conscious organizations can deploy with confidence. Within the first year, the Senior Engineering Manager should help turn a fast-moving early product into a team and engineering system that can scale by helping the team:

• Define what “production-ready” means for Thunderbolt and consistently meet that bar.
• Create the clarity, ownership, and release confidence the team needs to ship quickly and sustainably.
• Raise the quality of the user-facing product experience while protecting codebase health, maintainability, privacy, and security.
• Build the lightweight structure needed for a senior team to do its best work without slowing down experimentation.
• Help build Thunderbolt for global scale, enterprise adoption, and real-world impact!

Work environment

This is afull-time, fully remote position. You’ll work with our passionate staff, open-source community members and partners from all over the globe. Strong communication and documentation skills are essential for effective collaboration across time zones and disciplines.

Compensation & benefits

We benchmark our base salaries to local markets and target the 60th percentile of the peer market. The salary ranges for this role are:

• US: $215,000 - $240,000 USD
• Canada: $190,000 - $220,000 CAD

In addition to competitive salaries, we offer a comprehensive benefits package designed to support your whole self.

Work & career

• Fully remote work & schedule flexibility
• Company-provided laptop
• Annual bonus program
• Monthly remote work stipend
• Annual professional development stipend
• Access to Coursera learning platform
• Industry conferences
• Company all-hands and team gatherings

Rest & play

• 24 days PTO per year (prorated)
• Your birthday
• Year-end company shutdown
• 9 wellbeing days
• Public holidays
• Other paid leave
• Quarterly wellbeing stipend for personal / family activities

Health & family

• 401(k) / RRSPcontributions
• Health, dental, & vision insurance
• Disability insurance
• Life insurance
• Employee assistance program
• Paid parental leave
• Paid sick days

Work eligibility

Applicants must reside in and have permanent work authorization for the country location(s) specified in the posting. We are unable to consider applicants outside of these markets at this time. And, we do not provide visa sponsorship.

How to apply

Please apply directly through our career page. We carefully review every cover letter and screening question, so take the time to answer each fully. We value authentic, thoughtful responses that reflect your own experience and perspective. It is fine to use AI tools to polish your writing, but your answers should be your own. Candidates who submit generic or unoriginal AI-generated responses may be disqualified from further consideration.

Our commitment to diversity, equity, and inclusion

MZLA believes in the value of diverse creative practices and forms of knowledge, and knows diversity, equity and inclusion are crucial to and enrich the company’s core mission. We encourage applications from everyone, including members of all equity-seeking communities, such as (but not limited to) women, racialized and Indigenous persons, persons with disabilities, persons of all sexual orientations, gender identities and expressions.

We are an equal opportunity employer. We do not discriminate on the basis of race (including hairstyle and texture), religion (including religious grooming and dress practices), gender, gender identity, gender expression, color, national origin, pregnancy, ancestry, domestic partner status, disability, sexual orientation, age, genetic predisposition, medical condition, marital status, citizenship status, military or veteran status, or any other basis covered by applicable laws. MZLA will not tolerate discrimination or harassment based on any of these characteristics or any other unlawful behavior, conduct, or purpose.

We will ensure that qualified individuals with disabilities are provided reasonable accommodations to participate in the job application or interview process, to perform essential job functions, and to receive other benefits and privileges of employment, as appropriate. Please contact us at hiringaccommodations@thunderbird.net to request accommodation.

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