← All roles

Senior Mobile Engineer, iOS

Mozilla· Thunderbird
Apply on company site
Hybrid (Remote US)$123k - $144kfull-timePosted 2mo ago

About the role

Senior iOS-focused software engineer responsible for designing, developing, and evolving Thunderbird’s iOS application. Collaborates with mobile engineers, product, UX, and open-source contributors to deliver a high-quality, secure, accessible, and scalable iOS experience.

Responsibilities

  • 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.

Qualifications

  • 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.
  • 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.

Skills

Required:SwiftSwiftUIiOS frameworksSecurity and privacyCode review and testingGit and collaboration

Benefits

  • 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
  • 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) contributions
  • Health, dental, & vision insurance
  • Disability insurance
  • Life insurance
  • Employee assistance program
  • Paid parental leave
  • Paid sick days
Last updated Sep 30, 2026. Interested? Apply on the company site.

About Mozilla

Internet for people, not profit

Mozilla is the not-for-profit behind the lightning fast Firefox browser. We put people over profit to give everyone more power online.

BrowserInternetNot-for-profitFirefox
Company profileWebsite

More open roles at Mozilla