Senior Mobile Engineer, iOS

Build and refine Thunderbird’s mobile products and platform architecture.

Improve scalability, performance, reliability, and user experience.

Develop a deep understanding of the codebase and architecture to confidently make changes across the entire stack.

Maintain strong debugging and testing practices across unit, integration, and automated testing.

Review code and guide improvements to architecture, testing, and development best practices.

Independently resolve complex issues involving performance, security, and cross-platform integration.

Monitor application health and address issues before they escalate.

Document technical decisions, system architecture, and team processes.

Own assigned projects, collaborating cross-functionally, from investigation and planning through development, validation, and delivery.

Ensure mobile development meets accessibility, security, and privacy standards.

7+ years of professional software development experience, including 2+ years in a Senior Software Engineer role.

3+ years of professional mobile application development experience.

Strong experience with Swift, SwiftUI, and iOS frameworks.

Deep knowledge of iOS architecture, design patterns, and performance optimization.

Experience delivering and maintaining complex, scalable, and reliable software.

Experience addressing technical debt and refactoring large or complex codebases.

Strong knowledge of mobile security, including encryption, secure storage, app signing, and vulnerability remediation.

Experience with communication and email protocols such as RSS, IMAP, POP, or Matrix, and familiarity with the IETF standards for CalDav or CardDav.

Advanced proficiency with Git and collaborative development workflows.

Strong debugging, testing, and problem-solving skills.

Strong attention to detail, curiosity, and a product-focused mindset.

The ability to work independently, take ownership, and collaborate across teams.

Respect for diverse skills, experiences, and perspectives.

Excellent async written communication skills; comfortable working with a geographically distributed team.

Ability to learn, evaluate, and responsibly use emerging technologies, including AI-enabled tools, to improve work processes.

Familiarity with Apple App Store and Google Play Store compliance guidelines.

Experience contributing to open-source projects or communities.

Proficiency in French, German, Japanese, or another widely supported Thunderbird language.

You’ll be successful in this role if you look beyond shipping features and improve the architecture, reliability, security, and long-term health of the product. You’re comfortable solving ambiguous problems, flagging risks early, documenting decisions, and collaborating across engineering, product, UX, users, and the open-source community.

Over time, your work will help Thunderbird’s iOS experience become more resilient, scalable, and easier for both staff and community contributors to build on.

This is a full-time, fully remote position. You’ll join a distributed team of Thunderbird staff, open-source community members, and contributors from around the world.

We rely on clear communication, thoughtful documentation, and collaborative decision-making to work effectively across time zones and disciplines.

Fully remote work & schedule flexibility

Company-provided laptop

Annual bonus program

Monthly remote work stipend

Annual professional development stipend

Access to Coursera l earning platform

Industry conferences

Company all-hands and team gatherings

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

401(k) / RRSP co ntributions

Health, dental, & vision insurance

Disability insurance

Life insurance

Employee assistance program

Paid parental leave

Paid sick days

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.

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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