Software Engineer - UI & API

📍 Job Overview

Job Title: Software Engineer - UI & API
Company: T-Mobile
Location: Bellevue, Washington, United States
Job Type: FULL_TIME
Category: Software Engineering / Full-Stack Development
Date Posted: August 18, 2025
Experience Level: Mid-Level (2-5 years)
Remote Status: On-site

🚀 Role Summary

• This role focuses on the design, development, and deployment of full-stack applications within T-Mobile's real-time payments division, emphasizing secure, scalable, and maintainable software solutions.
• Key responsibilities include building robust backend services and APIs using Java and Spring Boot, alongside developing responsive UIs with Angular and TypeScript.
• The position involves leveraging modern technologies, including AI-driven tools, microservices, and event-driven architectures, to enhance customer experience and business outcomes.
• Successful candidates will contribute to technical leadership, system design, cross-team collaboration, and continuous exploration of new engineering practices within an agile and data-driven environment.

📝 Enhancement Note: While the job title is "Software Engineer - UI & API," the description strongly suggests a full-stack development role with a focus on payment systems. The emphasis on backend (Java/Spring Boot) and frontend (Angular/TypeScript) development, along with API design, confirms this. The mention of AI-driven tools and modern architectures indicates a forward-thinking approach to software development within the operations and technology domain.

📈 Primary Responsibilities

• Design, develop, and deploy secure, scalable, and maintainable full-stack applications, with a particular focus on real-time payment systems.
• Construct robust backend services and RESTful APIs utilizing Java and the Spring Boot framework.
• Build responsive and user-friendly web interfaces leveraging Angular and TypeScript.
• Integrate and utilize AI-driven tools such as GitHub Copilot and ChatGPT to enhance development efficiency and code quality.
• Implement comprehensive unit, integration, and end-to-end tests to ensure high-quality, reliable software.
• Actively participate in code reviews, contribute to architectural and design discussions, and engage in agile development ceremonies.
• Optimize application performance, identify bottlenecks, and debug issues across the entire technology stack.
• Contribute to low-level system design and effectively break down user stories into actionable development tasks.
• Collaborate with peers and stakeholders across different teams to deliver integrated, end-to-end technical solutions.
• Continuously explore, learn, and apply new technologies and engineering best practices to drive innovation.
• Apply AI and automation techniques to improve customer experience and achieve defined business objectives.
• Develop a deep understanding of T-Mobile's services and how the Digital Payment Services team contributes to customer value.

📝 Enhancement Note: The responsibilities highlight a blend of individual contribution and collaborative effort, typical for a mid-level engineer. The emphasis on payment systems and regulatory frameworks (PCI, USGCI, SOX) suggests that understanding business context and compliance will be crucial for success in this role, aligning it with operational excellence in financial technology.

🎓 Skills & Qualifications

Education:

• Bachelor's Degree in Computer Science, Engineering, or a closely related technical field is required.

Experience:

• 2-4+ years of professional software development experience, with a strong emphasis on full-stack development methodologies.
• Proven experience in designing and building scalable applications.
• Experience in a role that requires collaboration with cross-functional teams.

Required Skills:

• Proficiency in Java for backend development, including experience with the Spring Boot framework.
• Strong command of Angular for front-end development, coupled with expertise in TypeScript.
• Solid understanding of RESTful APIs, including design principles, implementation, and consumption.
• Knowledge of HTTP protocols and asynchronous messaging patterns, essential for distributed systems.
• Experience with writing comprehensive unit, integration, and end-to-end tests to ensure code quality and application stability.
• Familiarity with agile development methodologies and participation in agile ceremonies (e.g., sprint planning, daily stand-ups, retrospectives).
• Experience with code review processes, providing and receiving constructive feedback.
• Ability to debug and optimize performance across the full software stack.

Preferred Skills:

• Familiarity with NoSQL databases, such as MongoDB, Cassandra, or DynamoDB, for flexible data storage solutions.
• Experience working with or understanding of regulatory frameworks like PCI (Payment Card Industry Data Security Standard), USGCI (United States Government Commercial Information), or SOX (Sarbanes-Oxley Act).
• Prior experience working with payment systems and a foundational understanding of transaction lifecycles and payment processing flows.
• Exposure to Kafka or other event-driven messaging platforms, demonstrating an understanding of asynchronous communication patterns.
• Experience with AI-driven development tools like GitHub Copilot or ChatGPT.

📝 Enhancement Note: The required skills clearly define a full-stack engineer proficient in Java/Spring Boot and Angular/TypeScript. The preferred skills indicate a specialization in financial technology, highlighting the importance of understanding payment systems, regulatory compliance, and asynchronous communication patterns for this role. The mention of AI tools suggests a modern development environment.

📊 Process & Systems Portfolio Requirements

Portfolio Essentials:

• Showcase examples of full-stack applications, demonstrating proficiency in both backend API development and frontend UI implementation.
• Include case studies highlighting projects where process optimization or efficiency improvements were achieved through software development.
• Provide evidence of system implementation, particularly in areas related to financial transactions or data management.
• Demonstrate the ability to measure and articulate the Return on Investment (ROI) or business impact of developed software solutions.

Process Documentation:

• Documented workflows for designing and optimizing application architectures, with a focus on scalability and maintainability.
• Examples of implemented automation within development pipelines or application functionalities.
• Evidence of performance measurement, analysis, and iterative improvement cycles applied to software projects.

📝 Enhancement Note: While a formal portfolio isn't explicitly requested, candidates are expected to demonstrate their capabilities through their experience and potentially through interview challenges. The emphasis on full-stack development, efficiency, and impact suggests that showcasing projects involving complex systems, clear problem-solving, and measurable results will be highly advantageous.

💵 Compensation & Benefits

Salary Range:

• The base pay range for this position is $92,500 - $166,800 annually.
• 📝 Enhancement Note: This salary range is competitive for a Mid-Level Software Engineer in the Bellevue, Washington area, reflecting the specific technical skills, industry experience (payments), and responsibilities of the role. The actual salary will be determined based on factors such as candidate qualifications, experience, and work location.

Benefits:

• Comprehensive Health Coverage: Medical, Dental, and Vision insurance plans.
• Financial Wellness: Flexible Spending Account, 401(k) plan, Employee Stock Grants, and Employee Stock Purchase Plan.
• Work-Life Balance: Paid Time Off, approximately 4 weeks for new full-time employees, and up to 12 paid holidays annually.
• Family Support: Paid Parental and Family Leave, Family Building Benefits, back-up care, enhanced family support, and childcare subsidy.
• Professional Development: Tuition assistance and college coaching to support continuous learning.
• Disability & Insurance: Short-term and long-term disability coverage, voluntary AD&D, accident, life, and long-term care insurance options.
• Additional Perks: Mobile service & home internet discounts, pet insurance, and access to commuter and transit programs.

Working Hours:

• Standard working hours are typically 40 hours per week, aligning with project deadlines and team collaboration needs.
• 📝 Enhancement Note: While a standard 40-hour work week is mentioned, the dynamic nature of payment systems and project delivery may require flexibility. The "Un-carrier" culture suggests a results-oriented environment where exceptional performance is valued.

🎯 Team & Company Context

🏢 Company Culture

Industry:

• Telecommunications. T-Mobile is a leading wireless network operator known for its customer-centric approach and disruptive market strategies. The role is within the Digital Payment Services team, an area critical for financial transactions and customer experience.
• 📝 Enhancement Note: Operating within the telecommunications sector, particularly in payment services, requires a focus on reliability, security, and customer satisfaction. The company's "Un-carrier" ethos emphasizes innovation, agility, and a willingness to challenge traditional norms.

Company Size:

• T-Mobile is a large enterprise, with a significant number of employees globally. This scale offers opportunities for impactful work, exposure to diverse technologies, and career advancement within a well-established organization.
• 📝 Enhancement Note: The large company size implies structured processes, established career paths, and a wide array of resources, but also potentially a need for engineers to navigate complex organizational structures and processes.

Founded:

• T-Mobile USA was founded in 1994. The company has a history of growth and transformation, culminating in its merger with Sprint, further solidifying its position in the market.
• 📝 Enhancement Note: A long-standing presence in the industry suggests a stable work environment with opportunities to learn from seasoned professionals and contribute to long-term strategic initiatives.

Team Structure:

• The Software Engineer will join a cross-functional team of payments professionals and software engineers.
• This team is responsible for the architecture and design of critical software components within real-time payments.
• Collaboration with peers across different teams is a key aspect of delivering end-to-end solutions.
• 📝 Enhancement Note: The cross-functional nature of the team suggests a collaborative environment where engineers work closely with product managers, designers, and potentially business analysts. Reporting lines are likely within a dedicated engineering or technology division.

Methodology:

• The team champions a culture of innovation and data-driven decision-making.
• They embrace AI-driven tools to enhance development and operations.
• Agile practices are followed, indicating iterative development, flexibility, and continuous feedback loops.
• Radical transparency is a core value, suggesting open communication and sharing of information within the team and across the organization.
• 📝 Enhancement Note: The adoption of AI and agile methodologies points to a modern, efficient, and adaptive development process. This approach is crucial for staying competitive in the fast-paced payments and telecommunications industries.

Company Website:

• https://www.t-mobile.com/

📈 Career & Growth Analysis

Operations Career Level:

• This is a Mid-Level Software Engineer position, typically requiring 2-5 years of professional experience. It signifies a transition from junior-level tasks to taking ownership of features, contributing to design decisions, and mentoring junior engineers.
• 📝 Enhancement Note: Mid-level engineers are expected to be largely autonomous in their day-to-day tasks, capable of solving complex problems independently, and contributing significantly to team goals.

Reporting Structure:

• The role likely reports to a Software Engineering Manager or a Team Lead within the Digital Payment Services division.
• Close collaboration with product managers, architects, and other engineers is expected.
• 📝 Enhancement Note: The reporting structure will provide guidance and mentorship, while cross-functional collaboration will expose the engineer to various aspects of the product lifecycle and business operations.

Operations Impact:

• This role has a direct impact on T-Mobile's real-time payment systems, which are critical for revenue generation and customer satisfaction.
• By improving the efficiency, reliability, and security of these systems, the engineer contributes to seamless financial transactions and a positive customer experience.
• The use of AI and modern technologies aims to drive business outcomes by enhancing operational efficiency and customer engagement.
• 📝 Enhancement Note: The impact of this role is significant, as payment systems are foundational to a telecommunications company's operations and financial health. Contributions here directly affect revenue streams and customer trust.

Growth Opportunities:

• Skill Specialization: Deepen expertise in specific areas like payment systems, API design, front-end frameworks (Angular), or backend technologies (Java/Spring Boot).
• Leadership Development: Opportunities to take on technical leadership roles, lead small feature teams, or mentor junior engineers.
• Cross-Functional Exposure: Gain experience working with various departments, understanding different business functions and their reliance on technology.
• Technology Exploration: Continuous learning and application of new technologies, including AI and cloud-native architectures, supported by the company's culture of innovation.
• Career Pathing: Potential progression to Senior Software Engineer, Staff Engineer, Architect, or management roles within T-Mobile's technology organization.
• 📝 Enhancement Note: T-Mobile's "jungle gym" analogy for career growth suggests a dynamic environment where employees are encouraged to explore different roles and skill sets, fostering broad professional development.

🌐 Work Environment

Office Type:

• The role is based at T-Mobile's headquarters in Bellevue, Washington, indicating an on-site work environment.
• 📝 Enhancement Note: Working from headquarters often provides greater access to resources, networking opportunities, and direct interaction with leadership and key stakeholders.

Office Location(s):

• Bellevue, Washington, Building 4.
• 📝 Enhancement Note: Bellevue is a major technology hub in the Pacific Northwest, offering a vibrant ecosystem of tech companies and talent.

Workspace Context:

• The workspace is likely to be a modern office environment designed to foster collaboration and innovation.
• Access to T-Mobile's internal technology stack, development tools, and resources will be provided.
• Opportunities for interaction with a diverse team of engineers and payments professionals are abundant.
• 📝 Enhancement Note: The emphasis on AI-augmented tools and a modern stack suggests a technologically advanced workspace that supports efficient development and collaboration.

Work Schedule:

• The standard work schedule is 40 hours per week.
• 📝 Enhancement Note: While a standard schedule is outlined, the nature of payment systems may occasionally require flexibility to meet critical deadlines or address urgent operational issues. The company culture likely supports a results-oriented approach.

📄 Application & Portfolio Review Process

Interview Process:

• Initial Screening: HR or recruiter screen to assess basic qualifications, experience, and cultural fit.
• Technical Assessments: May include coding challenges, live coding sessions, or take-home assignments focusing on Java, Spring Boot, Angular, and API design.
• Technical Interviews: In-depth discussions with engineers and team leads to evaluate problem-solving skills, system design capabilities, and understanding of core concepts.
• Behavioral Interviews: Questions designed to assess teamwork, communication, leadership potential, and alignment with T-Mobile's values and culture.
• Final Round: Potentially includes discussions with hiring managers or senior leadership, possibly focusing on strategic thinking and long-term impact.
• 📝 Enhancement Note: Expect the interview process to be rigorous, covering both technical depth and the ability to collaborate effectively within a team. Be prepared to discuss specific projects and demonstrate problem-solving methodologies.

Portfolio Review Tips:

• If a portfolio is requested or can be shared, focus on projects that demonstrate full-stack capabilities, particularly those involving backend APIs and frontend UIs.
• Highlight projects related to financial systems, transaction processing, or data-intensive applications.
• Clearly articulate the technical challenges faced, the solutions implemented, and the impact of your work using metrics (e.g., performance improvements, efficiency gains, error reduction).
• Showcase experience with Java, Spring Boot, Angular, TypeScript, and API design.
• If possible, include examples of work involving asynchronous messaging, databases (SQL/NoSQL), and any exposure to payment systems or regulatory compliance.
• 📝 Enhancement Note: Even without a formal portfolio, be ready to discuss specific projects in detail during interviews, treating your resume as a reference point for your experience.

Challenge Preparation:

• Coding Challenges: Practice coding problems on platforms like LeetCode, HackerRank, or Coderbyte, focusing on algorithms, data structures, and language proficiency (Java, JavaScript/TypeScript).
• System Design: Prepare for system design questions by understanding concepts like scalability, availability, fault tolerance, API design patterns, database choices, and caching strategies. Consider how to design a real-time payment system.
• Behavioral Questions: Use the STAR method (Situation, Task, Action, Result) to prepare answers for questions about teamwork, problem-solving, handling challenges, and leadership.
• Domain Knowledge: Refresh your understanding of RESTful APIs, HTTP, asynchronous messaging, and basic concepts of payment processing and security if possible.
• AI Tools: Be prepared to discuss how you have used or would use AI-driven tools like GitHub Copilot to enhance your development workflow.
• 📝 Enhancement Note: Focus on demonstrating not just technical correctness but also clarity of thought, efficient problem-solving, and good communication during technical challenges.

🛠 Tools & Technology Stack

Primary Tools:

• Backend: Java, Spring Boot, RESTful APIs
• Frontend: Angular, TypeScript
• Development Environment: Likely includes IDEs like IntelliJ IDEA or VS Code, build tools like Maven or Gradle, and version control systems like Git.
• AI-Augmented Tools: GitHub Copilot, ChatGPT (mentioned explicitly)

Analytics & Reporting:

• Tools for monitoring application performance, logging, and error tracking (e.g., Splunk, ELK stack, Datadog).
• Data analysis tools may be used for understanding system usage and identifying areas for optimization.

CRM & Automation:

• While not explicitly mentioned for this role, T-Mobile utilizes various CRM systems and automation tools across the organization. Knowledge of CRM data flow and integration principles can be beneficial.
• 📝 Enhancement Note: Proficiency with Java, Spring Boot, and Angular is paramount. Familiarity with modern development practices, CI/CD pipelines, and cloud platforms (though not specified, often relevant) would be advantageous.

👥 Team Culture & Values

Operations Values:

• Innovation: Embracing new technologies and approaches, including AI, to drive progress.
• Data-Driven Decisions: Utilizing data to inform choices and measure impact.
• Customer Focus: Prioritizing customer needs and experience in all development efforts.
• Agility: Adapting quickly to changing requirements and market conditions.
• Inclusivity: Fostering a diverse and welcoming environment.
• Radical Transparency: Open communication and sharing of information.
• Passion for Growth: Encouraging continuous learning and professional development.
• 📝 Enhancement Note: The company culture emphasizes a forward-thinking, customer-centric, and collaborative approach, which is crucial for operational excellence in a dynamic industry like telecommunications and payments.

Collaboration Style:

• Cross-functional collaboration is a core expectation, working closely with peers and stakeholders across different teams.
• Active participation in code reviews and design discussions encourages knowledge sharing and collective problem-solving.
• Agile ceremonies facilitate regular communication and alignment within the development team.
• 📝 Enhancement Note: The collaborative style is essential for delivering complex, integrated solutions in a large organization, ensuring that different parts of the business work cohesively towards common goals.

⚡ Challenges & Growth Opportunities

Challenges:

• Scalability and Performance: Ensuring real-time payment systems remain performant and scalable under high load.
• Security and Compliance: Adhering to strict security standards and regulatory requirements (PCI, SOX) in a financial transaction environment.
• Integration Complexity: Integrating with various internal and external systems within a large enterprise.
• Adapting to New Technologies: Keeping pace with rapid advancements in AI and software development practices.
• Cross-Team Dependencies: Navigating dependencies and communication across multiple teams to deliver end-to-end solutions.
• 📝 Enhancement Note: These challenges provide significant opportunities for learning and developing expertise in critical areas of software engineering and operational efficiency.

Learning & Development Opportunities:

• Formal Training: Access to T-Mobile's extensive learning resources, including tuition assistance and college coaching.
• Mentorship: Opportunities to learn from experienced engineers and leaders within the organization.
• On-the-Job Learning: Exposure to modern technologies, complex systems, and best practices through daily work.
• Industry Exposure: Working with cutting-edge technologies like AI and contributing to mission-critical payment systems.
• Conferences & Certifications: Potential for support to attend industry conferences or pursue relevant certifications.
• 📝 Enhancement Note: T-Mobile's commitment to employee growth, coupled with the nature of the role, offers a fertile ground for continuous professional development in high-demand technology areas.

💡 Interview Preparation

Strategy Questions:

• Technical Design: "How would you design a scalable and secure real-time payment processing system?" or "Describe the architecture of a microservice-based application handling financial transactions."
• Problem Solving: "You're experiencing a performance bottleneck in a Java API; how would you diagnose and resolve it?" or "How would you approach debugging a UI issue that only occurs intermittently in Angular?"
• Collaboration & Teamwork: "Describe a time you had a disagreement with a team member on a technical approach and how you resolved it." or "How do you ensure your code is well-documented and understandable for other team members?"
• AI Integration: "How do you see AI tools like GitHub Copilot impacting the software development lifecycle, and what are their limitations?"
• Domain Specific: "What are the key considerations when developing systems that handle payment card data?" or "Explain the concept of asynchronous messaging in the context of a payment system."
• 📝 Enhancement Note: Prepare to discuss your experience with Java, Spring Boot, Angular, and API design using specific examples. Be ready to articulate your problem-solving process and your approach to building robust, scalable, and secure applications.

Company & Culture Questions:

• Research T-Mobile's recent performance, strategic initiatives (especially in digital payments or customer experience), and their "Un-carrier" brand values.
• Be prepared to discuss why you are interested in T-Mobile and this specific role, and how your skills and career goals align with the company's direction.
• Understand the importance of agile methodologies, data-driven decisions, and AI integration within the team.
• 📝 Enhancement Note: Demonstrating genuine interest in T-Mobile's mission and culture, beyond just the technical aspects, will be crucial for cultural fit assessment.

Portfolio Presentation Strategy:

• If presenting a portfolio, focus on showcasing end-to-end application development.
• For each project, clearly outline the problem statement, your role, the technologies used (Java, Spring Boot, Angular, etc.), the technical challenges, your solutions, and the measurable outcomes or impact.
• Be prepared to walk through code snippets or architecture diagrams if relevant.
• Emphasize how your work contributes to efficiency, scalability, and reliability, especially in contexts similar to payment systems.
• 📝 Enhancement Note: If no formal portfolio is required, be ready to use your resume as a guide to walk through your most relevant projects and achievements, highlighting your full-stack capabilities and impact.

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To apply for this operations-focused Software Engineer position:

• Submit your application through the provided link on the T-Mobile careers portal.
• Resume Optimization: Tailor your resume to highlight your experience with Java, Spring Boot, Angular, TypeScript, RESTful APIs, and any experience with payment systems or related technologies. Quantify your achievements with metrics whenever possible to demonstrate operational impact.
• Portfolio Preparation: While not explicitly required, be ready to discuss relevant projects from your experience that showcase your full-stack development skills, problem-solving abilities, and contributions to system efficiency or performance.
• Interview Practice: Prepare for technical interviews by reviewing core computer science concepts, practicing coding challenges, and familiarizing yourself with system design principles relevant to scalable applications and APIs. Practice answering behavioral questions using the STAR method.
• Company Research: Deeply research T-Mobile's business, its "Un-carrier" culture, and its position in the telecommunications and digital payments landscape to articulate your interest and alignment.

⚠️ Important Notice: This enhanced job description includes AI-generated insights and operations industry-standard assumptions. All details should be verified directly with the hiring organization before making application decisions.