Sr Engineer, Software

T-Mobile • Bellevue, WA

29d

About The Position

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 looking for a highly skilled Senior Software Engineer to join the T-Life Backend Engineering team. This team builds and scales the core backend systems that power T-Mobile’s customer-facing mobile experiences, including the T-Life app. In this role, you will develop Java-based microservices and APIs that support millions of users—enabling scalable, secure, AI-enhanced, and high-performance experiences across T-Mobile’s digital ecosystem. The ideal candidate brings strong Java expertise, deep knowledge of cloud-native engineering practices, and experience deploying resilient services in production. We are also seeking engineers who actively leverage AI-assisted development tools to accelerate delivery, improve code quality, and drive engineering efficiency.

Requirements

• 7+ years in backend or platform engineering, primarily using Java (8+)
• Proven experience building and scaling RESTful APIs
• Strong understanding of microservice architecture, event-driven systems, and distributed service orchestration
• Experience with cloud platforms (AWS, Azure, or equivalent)
• Hands-on experience with CI/CD pipelines, automated testing, and API monitoring
• Proficiency with NoSQL (MongoDB, Cassandra) and relational databases
• Strong knowledge of security best practices (OAuth, HTTPS, token lifecycle management)
• Ability to debug production issues, create monitoring/alerting, and own services end-to-end
• Demonstrated experience using AI-based engineering tools (e.g., GitHub Copilot, code assistants, automated testing frameworks, AI-driven debugging or triage) to enhance developer productivity
• Bachelor’s degree in Computer Science, Engineering, or related technical field (or equivalent practical experience)
• At least 18 years of age
• Legally authorized to work in the United States

Nice To Haves

• Experience building APIs used by mobile clients
• Familiarity with Kafka or event-streaming platforms
• Knowledge of Docker, Kubernetes, and container orchestration
• Experience with geolocation, personalization, or session management systems
• Exposure to analytics tools, observability platforms (Splunk, Datadog), or APM technologies
• Experience developing or integrating AI/ML-powered features or developer workflows

Responsibilities

• Lead the design and development of scalable Java microservices supporting mobile feature delivery at high scale.
• Build secure, reliable APIs consumed by iOS, Android, and web/internal systems.
• Write clean, maintainable code backed by comprehensive unit, integration, and contract tests.
• Ensure code meets high standards for performance, reliability, observability, and security.
• Collaborate with system engineers to align backend data flows, service contracts, and integration patterns.
• Provide mentorship and conduct regular code reviews to promote technical excellence.
• Use AI-based development tools (e.g., AI pair programming, automated refactoring, intelligent code generation) to speed up development cycles, enhance code quality, and reduce manual effort.
• Drive platform-level improvements in event streaming, configuration management, and service health visibility.
• Explore and adopt emerging technologies, including AI-driven developer tooling, that reduce latency, simplify deployments, or enhance resilience.
• Identify opportunities for refactoring or architecture modernization aligned with API-first, mobile-first principles.
• Champion the use of AI for tasks such as documentation generation, test creation, triage automation, and code optimization.
• Partner with mobile engineers to define backend contracts and troubleshoot client-service interactions.
• Work closely with Product, QA, and UX teams to ensure backend APIs meet functionality and experience requirements.
• Participate in PI planning, sprint ceremonies, and cross-functional release activities across the T-Life ecosystem.
• Collaborate with teams to identify high-impact use cases for AI that improve delivery velocity and operational efficiency.
• Create clear, comprehensive technical documentation for backend services, API contracts, and architectural patterns.
• Contribute to internal design documents, Confluence resources, and onboarding guides.
• Leverage AI tools to assist in generating and maintaining high-quality documentation.

Benefits

• 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.
• 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.
• eligible employees can also receive mobile service & home internet discounts, pet insurance, and access to commuter and transit programs!

What This Job Offers

• Job Type: Full-time
• Career Level: Mid Level
• Number of Employees: 5,001-10,000 employees