Staff Mobile Engineer, iOS

Why Thunderbird?

MZLA Technologies Corporation (MZLA) is a wholly owned, for-profit subsidiary of the Mozilla Foundation and home to Thunderbird, our flagship open-source email and productivity platform empowering more than 20 million people around the world. While part of the Mozilla portfolio of companies, MZLA operates independently in both identity and organizational structure from the Mozilla Foundation and Mozilla Corporation.

Everything we build at MZLA is open source, developed transparently and in collaboration with a global community of contributors. This open approach shapes not only our products but also how we work: collaboratively, inclusively, and with a shared commitment to building technology that puts users first. We believe privacy and productivity should coexist, and that people deserve powerful digital tools without surrendering control of their data.

MZLA is a small but growing team of 50+ people distributed across seven countries. As we evolve Thunderbird from a single application into a suite of privacy-respecting productivity tools, we’re introducing new products and services that remain independent of big tech ecosystems. Our unique revenue model combines community donations that keep Thunderbird freely available with subscriptions for new cloud-based services, allowing us to grow and innovate while remaining independent and true to our values.

To learn more, visit www.thunderbird.net

The Opportunity:

The Staff Software Engineer, Mobile is a senior individual contributor who brings deep iOS expertise to the design, development, and evolution of Thunderbird’s iOS application. This role works on complex and ambiguous technical problems, leads significant mobile initiatives, and contributes to architectural decisions in collaboration with other senior engineers and engineering leadership.

You’ll work closely with mobile engineers, product management, UX, and other partners to deliver high-quality iOS experiences that meet high standards for performance, reliability, accessibility, security, and maintainability. The ideal candidate demonstrates deep mobile expertise, collaboration with engineering leadership and peers, ownership of technical decisions, and the ability to influence, mentor, and guide the work of other engineers.

You’ll play a critical role in delivering exceptional user experiences by translating strategy into action and ensuring technical decisions align with MZLA’s mission and the objectives of the Thunderbird Project. This is a full-time, remote position working with colleagues across multiple regions and time zones.

What you’ll do:

• Tackle complex and ambiguous technical challenges in mobile development that require thoughtful design, planning, and coordination.
• Serve as a technical lead on major iOS initiatives, including feature development, architectural improvements, and targeted refactoring.
• Collaborate with senior engineers and engineering leadership on mobile technical direction and architectural decisions.
• Drive improvements to code quality by reducing technical debt and improving performance, stability, and build health.
• Partner closely with product and UX teams to ensure usability and accessibility are integral to iOS implementations.
• Write high-quality, testable, and maintainable iOS code, contributing to a consistent and reliable codebase.
• Mentor and support other engineers through code reviews, technical guidance, and knowledge sharing.
• Contribute to improving engineering practices and workflows, and stay current with iOS technologies and best practices.

What you’ll bring:

• 10+ years of professional software development experience, including significant experience working on complex mobile applications at senior level.
• Deep experience with Swift and iOS frameworks required
• Expertise with mobile architectures, platform constraints, and application lifecycle management on iOS.
• Proven experience leading complex technical work and contributing to architectural decisions, with the ability to act as a technical lead and mentor supporting the growth of other engineers.
• Solid understanding of software engineering best practices, including system design, testing strategies, and release considerations for mobile applications, along with working knowledge of mobile security and privacy practices.
• Experience with communication and email protocols such as RSS, IMAP, POP, or Matrix, and familiarity with the IETF standards for CalDav or CardDav.
• Proficiency with Git and collaborative development workflows, including code review and CI systems.
• Excellent communication skills, documentation skills, and the ability to work with a multi-disciplinary, geographically distributed team, with a product-oriented mindset considering user impact and business context.

Bonus points for:

• Experience contributing to or maintaining open-source projects.
• Familiarity with mobile release processes and app store requirements.
• Experience improving development processes, tooling, or workflows within a team.
• Experience with shared mobile components or cross-platform patterns is a plus.

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 MZLA Technologies Corporation.

This is a remote position. Strong communication and documentation skills are essential for effective collaboration across time zones and disciplines.

What you’ll get:

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: $150,000 - $170,000 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
• Latest Laptop
• Discretionary Annual Bonus Program
• Monthly Remote Work Stipend
• Annual Professional Development Stipend
• Access to Udemy Learning Platform
• Industry Conferences
• Company All Hands

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 also value authenticity. We want to hear your perspective, not a bot’s. It's fine to use AI to polish your writing, but not to write your answers. Candidates who submit unoriginal AI generated answers will be disqualified from further screening.

MZLA Technologies Corporation (MZLA) 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. Mozilla 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 athiringaccommodations@thunderbird.net to request accommodation.