Principal Engineer, Full Stack

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!

Advertising, meet the Un-carrier. We are standing up for Consumers and Advertisers to redefine an industry. Again. Ever feel like relevant, engaging, and safe advertising is an impossible ask? We are working to change that by building an advertising platform that allows brands and advertising agencies to engage real audiences with a customer-centric, privacy first approach.

This is not a product internal to T-Mobile; but one that is used by all the major advertising agencies in the United States and many of the top consumer product brands. Our team builds the enabling technology behind this revolution. We are a fast-moving team that builds, runs, and operates the T-Mobile Advertising Solutions platforms, including our audience building, rideshare, and retail media network solutions.

If you thrive on collaborating with cross-functional teams to solve complex problems, writing robust full stack code, and deploying scalable systems to the cloud, we want to talk to you. We're looking for an engineer who bring strong technical judgment, a product mindset, and the ability to own solutions end-to-end—from architecture to implementation to delivery—in a fast-moving AdTech environment.

The Principal Engineer Full Stack will lead the design, development, and deployment of scalable, high-performance systems across the full technology stack—including modern web frameworks, backend services, microservices, databases, and cloud infrastructure. You’ll collaborate closely with cross-functional teams to deliver innovative advertising solutions that balance performance, privacy, and user experience. You’ll serve as a technical leader, driving architecture decisions, mentoring engineers, and ensuring that our platforms are resilient, maintainable, and built for growth. While not a security-specific role, you will embed best practices for reliability and compliance into everything you build, helping to ensure the integrity of our infrastructure and applications.

Job Responsibilities: 

• Design, develop, and maintain end-to-end solutions across web front ends, APIs, microservices, and cloud infrastructure. 

• Collaborate with cross-functional teams including product, security, privacy, and operations to define and deliver features. 

• Lead system architecture discussions and technical decision-making for complex projects. 

• Write clean, testable, and efficient code in modern languages and frameworks. 

• Advocate for software engineering best practices, including CI/CD, automated testing, and observability. 

• Mentor team members and help foster a culture of learning, quality, and continuous improvement. 

 

Education: 

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

 

Work Experience: 

• 7–10 years of experience in full stack software development (front end + back end). 

• 7+ years of experience with databases, both relational and NoSQL, including schema design and optimization. 

• 4+ years of experience building and maintaining cloud-native systems using AWS, Azure, or GCP. 

• 3 + years of hands-on experience with DevOps practices and infrastructure as code (Terraform, CloudFormation, etc.). 

• Deep knowledge of modern web frameworks (e.g., React, Vue, Angular) and backend stacks (e.g., Node.js, Python, Java). 

• Solid understanding of microservices, APIs, and distributed systems.