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 and www.thunderbolt.io

The opportunity

Thunderbird is expanding beyond email with Thunderbolt, an open-source AI client designed for organizations that need more control over their data, infrastructure, and model choices.

We’re looking for a Staff Full-Stack Product Engineer: a full-stack engineer who ships production code and works directly with the partners and enterprise customers adopting Thunderbolt. You’ll spend most of your time in the codebase, building the features, integrations, and customizations that real deployments need. The rest of your time goes to working alongside technical partners to get those deployments running and keep them healthy.

Thunderbolt is delivered largely through technical partners and systems integrators who own the day-to-day customer relationship. You’ll be the engineer behind them. You’ll understand how a customer’s environment actually works, turn that understanding into working software, and fix the hard problems that need someone who knows the code.

What you’ll do

• Build and ship full-stack features, integrations, and customer-specific customizations in the Thunderbolt codebase, from front-end UI through APIs, services, and deployment configuration.
• Work directly with technical partners and enterprise customers to understand their environments, requirements, and constraints, and turn them into technical plans and working software.
• Support pilots, proofs of concept, and early production deployments, including partner-hosted and customer-controlled environments.
• Diagnose and fix complex issues across the application, infrastructure, identity and access, integration, and data-access layers, including bugs and regressions that need a code change and a release.
• Maintain customer-specific customizations over time so they keep working as the core product evolves.
• Spot which customer requests should become general product capabilities, and work with product and engineering to build them that way rather than as one-offs.
• Bring real-world deployment feedback into roadmap and prioritization discussions.
• Write the documentation, deployment guidance, and runbooks that let partners handle routine issues on their own.
• Use AI-assisted development tools thoughtfully to move quickly while keeping strong judgment about quality, security, and maintainability.

What you bring

• 10+ years of professional software engineering experience, including significant time building and shipping production applications with Staff-level scope and impact.
• Strong full-stack engineering skills, including modern TypeScript or JavaScript, component-based front-end frameworks, and back-end services, APIs, and integrations.
• Meaningful experience working directly with customers, partners, or systems integrators in a technical capacity where you also wrote the code. Forward deployed, embedded, consulting, and implementation engineering work all count.
• Experience building or supporting AI-enabled applications, such as LLM platforms, RAG systems, agents, enterprise search, or data connectors.
• Solid understanding of enterprise deployment concerns, including authentication and identity providers, access control, self-hosted and hybrid infrastructure, observability, and reliability.
• Judgment about when to build something custom, when to generalize it into the product, and when to push back on a request.
• Clear communication skills with both technical implementers and non-technical stakeholders, including being honest about what the product can and can’t do today.
• Strong collaboration skills, including experience working closely with product managers, designers, engineers, and other cross-functional stakeholders.
• Comfort operating independently in an early-stage product where requirements, architecture, and processes are still taking shape.

Bonus points for

• Experience with self-hosted, private cloud, sovereign, or regulated deployment environments.
• Experience with Docker, Kubernetes, CI/CD, and cloud deployment.
• Experience working with European enterprise or public sector customers, or with data residency and sovereignty requirements.
• Experience supporting security reviews, privacy assessments, or enterprise procurement processes.
• Open-source contributions, or experience in open, highly collaborative engineering environments.

What success looks like

In your first few months, you’ll help land Thunderbolt’s first enterprise deployments. That means shipping the customizations those customers need, getting partner-hosted deployments stable, and fixing the issues that only show up in real environments.

Over time, success means each new deployment takes less custom work than the last. You’ll have turned one-off requests into reusable product capabilities, and partners will be able to handle routine issues without pulling in engineering.

Work environment

You’ll work with our passionate staff and open-source community members from all over the globe to support the mission and objectives of Thunderbird Technologies Corporation. In this role, you’ll also collaborate closely with engineering, product, design, enterprise-facing teams, technical partners, contractors, and external contributors working on Thunderbolt.

This is a remote, full-time position. Many of Thunderbolt’s customers and partners are based in Europe, so some regular overlap with European business hours is expected. 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: $185,000 - $220,000 USD

We may consider candidates with strong skills but less than the required experience. Title, level and compensation will be determined based on qualifications and experience.

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 toCoursera 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) contributions
• 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

Thunderbird 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. Thunderbird 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 [email protected] to request accommodation.

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