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. Job Responsibilities : 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 Required Education and Work Experience : 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) Required Knowledge, Skills and Abilities : 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 : Travel Required (Yes/No): Yes DOT Regulated : DOT Regulated Position (Yes/No): No Safety Sensitive Position (Yes/No): No Compensation Range: Bellevue, WA: $173,500 to $234,700 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,