Principal GenAI Software Engineer

Overview

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. 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 This role is essential for designing, implementing, and deploying scalable software generative AI-enabled solutions that meet customer requirements and support high availability environments. It involves collaborating with engineers to develop software components using modern CI/CD and deployment practices such as blue/green deployments, observability, canary deployments, Kubernetes feature flags and automated rollbacks. The role requires applying judgment to resolve complex technical issues and making recommendations for generative AI-enabled software architecture and design focusing on releasing and triaging deployed software.

Success is measured by the adoption and effectiveness of generative AI-enabled software solutions, technical leadership contributions, dependent teams adoption of recommended architectures and the ability to influence technology decisions. The work impacts the organization by enabling advanced software capabilities that improve operational efficiency and customer experience.

• Drive the architecture, design, and production deployment of enterprise-scale software development releases using generative AI systems, including LLM orchestration, Agent/Skill creation, retrieval-augmented generation, evaluation, and operational monitoring.
• Design and implement modular AI agents that connect to our core systems. Create clean abstractions that let non-technical users leverage these agents into useful workflows without writing code.
• Provide technical leadership by mentoring engineers and influencing technology and policy decisions across the organization.
• Establish GenAI engineering standards, reference architectures, and guardrails to ensure scalability, security, cost efficiency, and responsible AI use across multiple teams. Create templates, patterns, and documentation that accelerate everyone’s ability to deliver.
• Develop innovative generative-AI enabled software designs and improvements that enhance existing systems and processes.
• Produce clear technical documentation and architecture descriptions for internal and external stakeholders.
• Also responsible for other duties/projects as assigned by business management as needed.

• Bachelor's Degree plus 7 years of related work experience OR Advanced degree with 5 years of related experience (Required)
• Acceptable areas of study include Computer Science or Engineering (Required)
• 7-10 years technical engineering experience (Required)

• Proven track record of architecting and scaling enterprise-grade GenAI platforms (LLM orchestration, agent frameworks) that serve multiple teams and operate reliably in production.
• Experience establishing AI engineering standards, reference architectures, and governance models adopted across an organization.
• Demonstrated ability to design composable AI systems and internal developer platforms that enable non-technical users to build workflows without engineering support.
• Recognized technical leader with experience influencing cross-functional strategy, mentoring senior engineers, and driving AI adoption at the organizational level.
• Experience with release management & CI/CD deployment best practices.

• Communication (Required)
• Customer Service (Required)
• Analytics (Required)
• Technical Writing (Required)

• At least 18 years of age
• Legally authorized to work in the United States

Travel Required (Yes/No):
Yes

DOT Regulated Position (Yes/No):
No

Safety Sensitive Position (Yes/No):
No

Compensation Range for Bellevue, WA: $173,500 to $234,700

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

Corporate Bonus Target: 20%

The pay range above is the…