Underline starts with our people.

At Underline, we've rapidly built a culture around ownership, trust, community, and innovation. Underline is dedicated to cultivating a growth environment where people feel valued, work with a purpose of mission, are personally rewarded, and are professionally challenged.

Are you ready to join this team and transform American communities?

Underline was founded in 2019 with a singular mission: to ensure the vibrancy of our nation through building intelligent community infrastructure in a socially equitable manner. We work with American communities to design, finance, and construct open access fiber-optic networks. These networks are critical to secure internet access that’s fast, affordable, and fair. As open access networks, this infrastructure is also the essential foundation for distributed healthcare services, new wireless solutions, and resilient infrastructure including modernized water systems and responsible energy creation. Our first two projects are in Colorado Springs and Fountain, Colorado.

Underline is seeking a Senior Full-Stack Engineer to join our small team building the software that runs a fiber network business.

This is a Senior role in the real sense.  You will write the specs and technical design documents, not receive them.  You will carry projects from a business conversation to production. This position uses agentic coding tools daily, with the same review discipline you would apply to a strong junior teammate’s pull request.

This is a U.S. Based position and travel to off-site company retreats is required.

• You would rather own an outcome than be handed a task.
• You can walk someone through code you shipped last month and explain every decision in it, whether you typed it or an agent did. 
• You know when good architecture is worth the delay and when it’s not, and you make that call yourself.
• You like early-stage environments, which means some of your work will be thrown away. 
• You work well alongside product managers, designers, and network engineers and know how to have meaningful, productive conversations.
• You want to work on infrastructure that strengthens American communities and makes access to connectivity more equitable.

• Features, end to end.  You take work from a loosely defined business need through design, implementation, deployment, and monitoring. Nobody hands you a spec. You write it and defend the tradeoffs in it. Sometimes the right answer is that the whole thing should be smaller, and we expect you to say so.
• ‍AI-assisted delivery. You use Claude Code as a core part of how you work: decomposing problems so agents make real progress, running parallel threads when that helps, and reading every diff before it lands. You also improve how the team does this, from the CLAUDE.md files and MCP servers to the gates that make agent output safe to trust.‍
• The stack. Backend services in Go, event-driven integrations over NATS, GraphQL and REST APIs, and the Ember front-end that consumes them. You care what the screen looks like and how it feels to use.‍
• The quality bar. Tests, CI/CD, observability, and performance are your responsibility, not a separate team’s. The more code agents generate, the more this matters.‍
• The team. You make pragmatic calls under ambiguity, write down the patterns worth repeating, interview candidates, and make the engineers around you better with these tools.

• 8+ years of professional software engineering experience, including production ownership across the stack. 
• Current, demonstrated practice with agentic coding tools.  
• Deep expertise in Go and strong command of PostgreSQL, including schema design and query optimization.
• GraphQL and REST APIs in production, plus TypeScript and a modern front-end framework (Ember, React, Vue) and a utility-first CSS framework like TailwindCSS. 
• Docker and Kubernetes in production, and event-driven architectures on a message system such as NATS, Kafka or RobbitMQ.
• Test-driven development and CCI, plus a solid grasp of web security, authentication and authorization. 
• Strong debugging across distributed systems including code you did not write.

• Experience in telecom, broadband, or infrastructure companies
• Local to the Dallas, TX area