Principal Engineer, Software - iOS

At T-Mobile, we invest in YOU!  Our Total Rewards Package ensures that employees get the same big love we give our customers.  All team members receive a competitive base salary and compensation package - this is Total Rewards. Employees enjoy multiple wealth-building opportunities through our annual stock grant, employee stock purchase plan, 401(k), and access to free, year-round money coaches. That’s how we’re UNSTOPPABLE for our employees!

Job Overview
We are seeking a highly skilled and experienced Principal iOS Engineer to help shape the future of the T Life App. In this role, you’ll work alongside a dedicated team of mobile developers to design, implement, and maintain high-quality iOS features that meet both business and customer needs. You’ll focus on building scalable, performant, and secure mobile solutions that enhance the customer experience within the T-Life app and T-Mobile’s broader app ecosystem. The ideal candidate brings deep expertise in iOS development—including modern architecture patterns, testing strategies, and performance optimization—paired with strong cross-functional collaboration skills. You’ll have the opportunity to influence technical direction, contribute features into production, mentor others, and grow within a culture that values innovation, impact, and continuous learning.
We pride ourselves on encouraging a culture of innovation, advocating for agile methodologies, and promoting transparency in all that we do. Join us in embodying the spirit of the 'Un-carrier' and make a tangible impact! Our team is dynamic where no day is the same, and we are diverse and inclusive passionate about growth and transformation. If you're up to the challenge, apply today!

Job Responsibilities:

• Design, develop, and maintain iOS applications using modern architecture patterns such as MVVM, MVC, Viper.

• Perform code reviews to ensure high-quality, maintainable, and secure code, while mentoring junior engineers.

• Collaborate with cross-functional teams including Product, Design, QA, and Backend engineers to deliver seamless experiences.

• Implement CI/CD pipelines for automated testing, building, and deployment.

• Ensure performance optimization and stability of iOS applications, addressing any critical bugs or crashes.

• Build and maintain modular, reusable components to streamline app development and improve code maintainability.

• Integrate third-party SDKs and APIs, ensuring secure and efficient interactions.

• Implement and enhance analytics tracking to monitor user behavior and app performance.

• Stay current with iOS platform updates and industry best practices, proposing innovative solutions to improve the app’s architecture and performance.

• Proactively identify opportunities for refactoring and improving the codebase to increase efficiency and maintainability.

• Collaborate in agile ceremonies such as sprint planning, retrospectives, and stand-ups to ensure smooth delivery of features.

• Continuously learn new technologies and advocate for best practices within the team.

• Contribute to technical documentation, ensuring knowledge is shared across the team.

• Documenting systems designs, presentations, and business requirements for consumption and consideration at the manager level.

Education and Work Experience:

• Bachelor's Degree Computer Science or Engineering (Required)

• 7-10 years Technical engineering experience. Required

Knowledge, Skills and Abilities:

• Communication (Required)

• Customer Service (Required)

• Analytics (Required)

• Technical Writing (Required)

Work Experience:

• 7+ years’ experience building complex applications for the iPhone or iPad using Swift /Objective-C/C++ with the iOS SDK and other frameworks (Required)

• Expertise in Swift and Objective-C, UIKit and SwiftUI, as well as knowledge of UI architecture and UI performance

• Strong knowledge of object-oriented programming, basic data structures and asynchronous programming. Experience with iOS app performance and metrics.

• Thorough conceptual and hands-on knowledge of architectural patterns preferably VIPER and best practices relating to complex mobile and progressive web apps.

• Solid grasp of mobile networking and REST Web Services

• Experience and understanding of large and complex code bases and architectures.

• Experience in API design, SDK architecture, and mobile software lifecycle development practices.

• Excellent verbal and written communication skills

Travel:
Travel Required (Yes/No):Yes
DOT Regulated:
DOT Regulated Position (Yes/No):No
Safety Sensitive Position (Yes/No):No

Base Pay Range: $133,500 - $240,700

Corporate Bonus Target: 20%

The pay range above is the general base pay range for a successful candidate in the role. The successful candidate’s actual pay will be based on various factors, such as work location, qualifications, and experience, so the actual starting pay will vary within this range.

At T-Mobile, employees in regular, non-temporary roles are eligible for an annual bonus or periodic sales incentive or bonus, based on their role. Most Corporate employees are eligible for a year-end bonus based on company and/or individual performance and which is set at a percentage of the employee’s eligible earnings in the prior year. Certain positions in Customer Care are eligible for monthly bonuses based on individual and/or team performance. To find the pay range for this role based on hiring location, https://paylookup.t-mobile.com/paylookup?reqID=REQ311510¶dox=1

At T-Mobile, our benefits exemplify the spirit of One Team, Together! A big part of how we care for one another is working to ensure our benefits evolve to meet the needs of our team members. Full and part-time employees have access to the same benefits when eligible. We cover all of the bases, offering medical, dental and vision insurance, a flexible spending account, 401(k), employee stock grants, employee stock purchase plan, paid time off and up to 12 paid holidays - which total about 4 weeks for new full-time employees and about 2.5 weeks for new part-time employees annually - paid parental and family leave, family building benefits, back-up care, enhanced family support, childcare subsidy, tuition assistance, college coaching, short- and long-term disability, voluntary AD&D coverage, voluntary accident coverage, voluntary life insurance, voluntary disability insurance, and voluntary long-term care insurance. We don't stop there - eligible employees can also receive mobile service & home internet discounts, pet insurance, and access to commuter and transit programs! To learn about T-Mobile’s amazing benefits, check out www.t-mobilebenefits.com.

Never stop growing!
As part of the T-Mobile team, you know the Un-carrier doesn’t have a corporate ladder–it’s more like a jungle gym of possibilities! We love helping our employees grow in their careers, because it’s that shared drive to aim high that drives our business and our culture forward. By applying for this career opportunity, you’re living our values while investing in your career growth–and we applaud it. You’re unstoppable!
T-Mobile USA, Inc. is an Equal Opportunity Employer. All decisions concerning the employment relationship will be made without regard to age, race, ethnicity, color, religion, creed, sex, sexual orientation, gender identity or expression, national origin, religious affiliation, marital status, citizenship status, veteran status, the presence of any physical or mental disability, or any other status or characteristic protected by federal, state, or local law. Discrimination, retaliation or harassment based upon any of these factors is wholly inconsistent with how we do business and will not be tolerated.
Talent comes in all forms at the Un-carrier. If you are an individual with a disability and need reasonable accommodation at any point in the application or interview process, please let us know by emailing [email protected] or calling 1-844-873-9500. Please note, this contact channel is not a means to apply for or inquire about a position and we are unable to respond to non-accommodation related requests.