Senior Mobile Engineer, iOS

RemoteSeniorPosted Aug 17, 2026

SwiftSwiftUIiOS+6 more

About this role

Build and evolve Thunderbird's iOS email application at MZLA, a Mozilla-owned nonprofit. Deep iOS expertise needed to deliver privacy-respecting communication tools for 20M+ global users in an open-source, fully remote environment.

Must have

7+ years professional software development experience with 2+ years in senior role

3+ years 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

Advanced proficiency with Git and collaborative development workflows

Strong debugging, testing, and problem-solving skills

Excellent async written communication skills for distributed team work

Ability to learn, evaluate, and responsibly use emerging technologies including AI-enabled tools

Technologies

iOSGitRESTSwiftJSONOpen sourceAICI/CDSwiftUI

Responsibilities

Build and refine Thunderbird's mobile products and platform architecture

Improve scalability, performance, reliability, and user experience

Develop deep understanding of codebase and architecture to make changes across 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 through delivery

Ensure mobile development meets accessibility, security, and privacy standards

Benefits

Training and career developmentEmployee Assistance ProgramPaid parental leaveHealth insuranceDental insuranceVision insuranceRetirement benefits with matchWellness allowanceHome office allowanceFlexible hoursCompetitive salaryRemote work

Amenities

Company-provided laptopAnnual bonus programMonthly remote work stipendAnnual professional development stipendAccess to Coursera learning platformIndustry conferencesCompany all-hands and team gatherings24 days PTO per year proratedYour birthday offYear-end company shutdown9 wellbeing daysPublic holidaysQuarterly wellbeing stipend for personal and family activities401(k) or RRSP contributionsDisability insuranceLife insurancePaid sick days