Stack Engineer II​/Sr; React + Python

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.

You’ll own features end‑to‑end across a modern Python/React stack, with a heavy dose of reliability, data plumbing, and “meet the enterprise where it is” integration work.

• Ship production features across React (frontend) and FastAPI (backend) that power our products (e.g., CAP AI, Atom Assist).
• Design and evolve APIs and Postgres schemas for performance, correctness, and auditability (migrations, indexing/partitioning, background data corrections).
• Containerize and deploy services with Docker/Podman and Kubernetes; help tune queues/workers (Redis, Rabbit
  
  MQ, Celery) for throughput, reliability and idempotency.
• Make data usable: build ingestion pipelines that prefer tabular sources (CSV/Excel/JSON) but gracefully handle the “we only have PDFs” reality - minimizing OCR, adding validation, and failing safely.
• Integrate with customer systems common in the industry (e.g., Maximo, Devon Way, Microsoft 365/Teams/One Note).
• Own reliability: reduce noise and fix root causes identified across Sentry and Netdata; add observability, back‑pressure, retries, and circuit breakers so we never lose a record.
• Collaborate with customers: join (lightweight) customer calls with utilities to understand constraints, scope integrations, and demo new capabilities.

Reality of the role:
You’ll bounce between product code, schema work, a gnarly data import, a Sentry investigation, and a customer demo environment - often in the same week.

• Build a Devon Way → CAP AI connector that ingests event data in tabular form, validates against our schemas, and supports safe reprocessing.
• Add a “simulate, then apply” workflow for CAP automations (human‑in‑the‑loop gates, dry‑run diffs, full audit trails, easy rollbacks).
• Cut a noisy Sentry class of errors by 30% by hardening a Celery task (idempotent writes, retry policy, dead‑letter queue).
• Implement license entitlements & usage reporting for a fleet customer renewal (clean server‑side enforcement plus UI visibility).
• Deliver a small Teams/One Note POC to integrate new data streams into Atom Assist.

• Frontend: React, JavaScript, HTML/CSS
• Backend: Python (FastAPI)
• Data/Infra: Postgre
  
  SQL, SQLite;
  Redis, Rabbit
  
  MQ, Celery
• Dev Ops: Docker/Podman, Kubernetes;
  Git Hub Actions
• Observability: Sentry, Netdata (and the dashboards you help us build)
• Quality: PyTest, Cypress
• Collab: Git/Git Hub

• Degree in CS or related field—or equivalent practical experience.
• You’ve shipped production React + FastAPI and can contribute independently within ~6 weeks.
• You care about correctness and safety: typed APIs, schema migrations with backfills, idempotent jobs, and tests that catch the sharp edges.
• You’re comfortable with customer‑facing engineering (a quick demo, a clarifying question, a pragmatic workaround).
• Clear, direct communicator; kind reviewer; steady under pressure.

Nice to have (not required):

• AI/ML or data‑pipeline experience (prompting, retrieval, feature stores, vector search).
• Prior startup experience.
• Exposure to nuclear/utility or other safety‑critical domains (aviation, med‑device, rail, etc.).

• CAP AI “toward 100% automation”: design safe guardrails (review gates, audit, simulation modes).
• Data connectors: unstructured PDFs, structured feeds; resilient syncs with Maximo/Devon Way; M365 integrations.
• Performance & reliability: fewer flakes, faster jobs, clearer dashboards, calmer alerts.

• Base salary: $125k - $150k (
• Equity: [–%] (meaningful ownership)
• Benefits: Unlimited vacation, health insurance, and more

• Full‑time, salaried
• Mon - Fri hybrid (Wed remote) expectation is ≥80% in‑office (Phoenix HQ)

If you want to apply modern AI and high‑quality software to problems that actually impact the future of clean energy, we’d love to meet you.