Backend Developer Intern Jobs in Mesa, AZ (NOW HIRING)

Nuclearn.ai builds AI-powered software for the nuclear and utility industries-tools that keep critical infrastructure reliable, efficient, and safe. Our software integrates AI-driven workflow, documentation, and research automation, and is already used at 60+ nuclear reactors across North America. You'll ship production code operators and engineers rely on every day.

We're growing quickly, expanding our team and our Phoenix HQ. The work is consequential: what you build helps real plants run safer and smarter.

Eligibility: U.S. citizenship or permanent residency (green card) is required due to DOE export compliance.

• Triage and resolve production bugs surfaced through Sentry - investigate root causes, write fixes, and ship patches across the stack
• Build and ship features on the product roadmap alongside senior engineers, contributing to major releases that reach 60+ nuclear reactors
• Write production code across the full stack - React on the frontend, FastAPI on the backend
• Learn modern delivery practices including CI/CD pipelines, code review workflows, and how to ship reliable software fast in a regulated industry

• Independently triage and fix incoming Sentry bugs - diagnose issues, scope the fix, and ship it to production
• Own a feature end-to-end - from understanding the requirement, to writing the backend API in FastAPI and the frontend UI in React, through code review and deployment
• Participate in design discussions and code reviews - collaborate with engineers on architectural decisions, surface trade-offs, and contribute best-practice recommendations to the team's standards

• Pursuing a degree in Computer Science, Software Engineering, or a related field or you've built enough on your own that a transcript doesn't tell the whole story
• Proficiency in Python and/or JavaScript/TypeScript - you've written real code, not just homework assignments, and you're comfortable picking up new frameworks quickly
• Strong independent problem-solving instincts - when you hit a wall, your first move is to dig in, read the logs, and trace the root cause yourself before escalating
• A bias toward durable solutions over quick patches - you don't just silence the alert, you ask why it fired and how to make sure it doesn't happen again
• You thrive in fast-paced environments - ambiguity doesn't paralyze you, it energizes you. You'd rather ship and iterate than wait for a perfect spec
• Comfortable using AI tools - you leverage AI to move faster, but you understand the underlying software architecture principles well enough to know when the output is right and when it's wrong

• Experience building APIs with Python and FastAPI - you've stood up endpoints, handled validation, and worked with async patterns before
• Familiarity with Docker and containerized environments - you understand images, containers, and can debug a failing build without panic
• Experience integrating agentic AI models into a product - you've gone beyond prompt-and-response to orchestrate models that complete complex, multi-step tasks autonomously

• Strengthen platform reliability - your bug fixes and troubleshooting directly resolve real customer pain points, making the product more robust for operators at 60+ reactors
• Ship features that customers actually use - you'll see the code you write go live and watch real users interact with it, not sit in a backlog
• Improve reliability metrics across the platform - fewer Sentry alerts, faster resolution times, and more stable releases as a direct result of your work
  

• Hourly: $25 - $35
  

• Part-time to full time, hourly internship
• In-office 4 days a week (Mon, Tue, Thu, Fri) at Phoenix HQ - the company is remote on Wednesdays, but interns work a 4-day in-office schedule to maximize hands-on collaboration and learning until demonstrated self-sufficiency
  

1. 20-min intro with the founder/hiring manager to trade context and assess mutual fit
2. Practical work sample (60-90 min; a real task in our stack)