Principal Backend Engineer

US Mobile is building the future of wireless communication. The goal: one unified network open to any person and any device, worldwide. Connection without walls. We’re getting there by empowering customers. All three major networks on one phone and one plan, plus home internet from Starlink. No lock-in. No commitments. Custom fit plans at every price point. 24/7 customer support with real people, empowered to help. We get real-time feedback from Reddit, surveys, and customer support informing product roadmaps and everything we do. It’s working — Consumer Reports named us the top-rated mobile carrier two years in a row.* And we’re building innovative systems that scale. A network agnostic tech stack. Agile, cross-functional teams built on trust and mutual respect. This work isn’t for everyone. If you work fast, flexibly, and collaboratively — without compromising standards — we want to hear from you. We're looking for an exceptional backend engineer and hands-on architect to help us scale and connect millions of devices to wireless networks. The projects and potential impact are incredible. We're looking for talented, ambitious, and entrepreneurial team members who are excited to tackle these challenges. You will:

Architect optimal solutions to our business problems

Deploy exciting new features

Help us scale to scale to 10’s of millions of customers & connected devices

Build quality tools and frameworks to ensure a high-quality product

Build systems to ensure continuous uptime

Responsibilities:

Develop and maintain RESTful APIs using Java (Spring Boot or related web frameworks) or Python (Flask, Django)

Design and implement asynchronous service communication using RabbitMQ or AWS SQS/SNS

Work with NoSQL databases like MongoDB for data modeling and storage

Collaborate with Product, QA, and DevOps teams to deliver reliable and scalable features

Write clean, testable, and well-documented code with unit and integration tests

Participate in system architecture design, code reviews, and performance tuning

Qualifications:

10+ years of experience with Java and Spring Boot

Strong experience with building and consuming REST APIs

Hands-on experience with message brokers such as RabbitMQ or AWS SQS/SNS

Familiarity with MongoDB or other NoSQL database technologies

Experience integrating and leveraging AI-assisted development tools such as Claude and Opencode to accelerate backend development, including code generation, debugging, and optimization of APIs and services.

Demonstrated ability to incorporate AI tools into the software development lifecycle, using Claude or Opencode for tasks like automated code reviews, documentation generation, and improving system design efficiency.

Solid understanding of Git, CI/CD workflows, and agile development practices

Excellent debugging, problem-solving, and communication skills

Excellent problem-solving and debugging skills

Strong communication and team collaboration skills

Benefits:

Health care coverage

Flexible paid time off

Gym reimbursement

Free cell phone service

Your choice of equipment + Bose QC/Apple Airpod Pro headphones

Think you're a good fit? Apply to learn more!