Principal Software Engineer

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This role sets technical direction for the systems that make T-Mobile's data usable across customer-facing applications, analytics, and AI-driven products. It involves designing and building high-performance services and APIs: the distributed data stores, low-latency access layers, and real-time sync mechanisms that deliver the right data to each consumer within strict latency and reliability targets. The role requires applying seasoned engineering judgment to solve complex systems challenges and to make recommendations on architecture, technology selection, and API and service design.

Success is measured by the scalability and reliability of these systems, the strength of technical leadership provided to engineers, and the ability to influence engineering decisions across the organization. The work impacts the organization by enabling the real-time, AI-ready capabilities that power better products and customer experiences.

• Design and build serving infrastructure for AI use cases including vector databases, graph databases, and agent-facing data patterns
• Design Infrastructure-as-Code blueprints for provisioning serving stores, sync pipelines, and APIs in a repeatable, governed way
• Partner with business teams and other technical teams to drive technical decision making, mentor engineers, and contribute to reusable blueprints and reference implementations.
• Design and develop high-performance data stores, real-time sync pipelines, and governed APIs that deliver data at the latency and scale each use case requires
• Drive engineering projects to deliver software solutions that meet technical requirements and quality standards
• Provide technical leadership by mentoring engineers and influencing technology and policy decisions across the organization
• Evaluate and apply technology strategies that align with business goals and system requirements
• Develop innovative 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)

• AI/ML Infrastructure
• Knowledge Graphs
• Vector Databases
• Streaming and caching architecture
• API Design and Governance
• MCP-Style tooling or agent facing data access patterns
• Data sync pipelines
• Analytics, Collaboration and Communication skills
• Analytical Thinking, Cloud computing, Customer Service and Leadership skills
• Software Development and Technical Writing skills

• 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

Bellevue, WA: $173,500 to $234,700

Atlanta, GA: $151,200 to $204,600

Total Target Cash Earnings Opportunity: $160,200 - $288,840

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

The Total Target Cash Earnings Opportunity represents the expected total cash compensation for this role at target performance, combining base salary and annual incentive opportunity. Actual earnings may be higher or lower depending on individual performance and overall company results.

The base pay range reflects the compensation component of this opportunity. The 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. To find the pay range for this role based on hiring location, .

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. Corporate employees are eligible for a year-end bonus…