Senior Fullstack (React.JS/.NET) Engineer Nucleus Labs $$$$

Madfish

Madfish

Software Engineering

Remote

Posted on Jun 5, 2026

Our client is a US-based remote-online-learning provider serving students through live digital instruction and operational student-support workflows. Together with Nucleus AI, the client is building the CCA Wellness Check Compliance Platform — a focused internal system for recording, tracking, and proving weekly student wellness checks.

The platform is designed to solve a concrete compliance and operations problem: the school needs a reliable way to confirm that weekly student wellness checks happened, maintain an auditable record, identify students who were not seen, and support escalation workflows when follow-up is required.

The MVP is time-sensitive and must be production-ready before the August teacher training window and September operational launch.

You’ll join a delivery team building a practical compliance platform from the ground up, working closely with product, engineering, QA, delivery, and client stakeholders.

Responsibilities

Fullstack Product Development

  • Build and maintain end-to-end product features across backend services and frontend application layers.
  • Work with frontend frameworks such as React, Angular, or Blazor to deliver user-facing functionality.
  • Integrate frontend applications with backend APIs and ensure smooth client-server communication.
  • Debug issues across the full application stack, including frontend behavior, API contracts, backend logic, database interactions, and deployment environments.
  • Collaborate with product, design, frontend, backend, and AI/ML teams to translate requirements into working product features.
  • Ensure frontend and backend changes are aligned, tested, and production-ready.

Backend Development & Architecture

  • Design and build scalable backend services using .NET Core / .NET Framework.
  • Develop RESTful APIs and microservices using ASP.NET Core.
  • Apply clean architecture principles and enforce coding standards.
  • Ensure systems are performant, secure, and maintainable.

Cloud & Infrastructure

  • Build and operate services on Microsoft Azure, including App Services, Functions, Azure SQL, and AKS.
  • Implement CI/CD pipelines using Azure DevOps or GitHub Actions.
  • Work with containerized environments such as Docker and Kubernetes.
  • Ensure system reliability, monitoring, and disaster recovery strategies.

Code Quality & Performance

  • Conduct code reviews and enforce best practices across backend and frontend codebases.
  • Implement unit, integration, and end-to-end testing where appropriate.
  • Monitor, profile, and optimize system performance across application layers.

Security & Compliance

  • Implement secure authentication and authorization using OAuth, JWT, or similar approaches.
  • Follow OWASP best practices.
  • Ensure data protection and system integrity.

Documentation & Improvement

  • Document technical decisions, API contracts, system behavior, and development workflows.
  • Continuously improve system design and development workflows.
  • Stay current with .NET, frontend, and cloud ecosystem developments.

Requirements

  • 5+ years of professional engineering experience, with strong commercial experience in .NET / C#.
  • Strong experience with ASP.NET Core, Web API, Entity Framework, and SQL Server.
  • Hands-on frontend experience with React, Angular, Blazor, or a comparable modern frontend framework.
  • Ability to build fullstack features from database and backend logic through API design and frontend implementation.
  • Experience integrating frontend applications with REST APIs and debugging client-server issues.
  • Hands-on experience with Microsoft Azure.
  • Experience with CI/CD pipelines and Git.
  • Experience with Docker and Kubernetes.
  • Strong understanding of SDLC, SOLID, and design patterns.
  • Experience with unit testing frameworks such as xUnit, NUnit, or MSTest.
  • Ability to debug and resolve complex issues across the full application stack.
  • Strong communication skills and ability to work closely with cross-functional teams.

Nice to Have

  • Experience with React or AngularJS.
  • Experience with messaging systems such as RabbitMQ, Kafka, or Azure Service Bus.
  • Familiarity with NoSQL databases such as Cosmos DB or MongoDB.
  • Azure certifications.
  • Experience in LMS, edtech, legal-tech, fintech, or data-heavy platforms.
  • Experience working with AI-assisted systems, AI/ML integrations, or data-driven product features.

What Matters for This Role

  • Ownership mindset — ability to take responsibility for features and systems end-to-end.
  • Strong backend engineering foundation combined with practical frontend delivery skills.
  • Comfort working in ambiguous, fast-moving environments.
  • Strong engineering judgment and pragmatic decision-making.
  • Ability to collaborate across backend, frontend, cloud, product, and AI/ML teams.