Full Stack Engineer (Python / React)

Nucleus is seeking a Full Stack Engineer proficient in Python and React to build automation, testing scaffolding, and orchestration layers that transform experimental prototypes into stable, production-ready MVPs. This role bridges backend services, frontend development, integration tooling, and developer platforms. Your work directly contributes to rapid experimentation by turning founder concepts into scalable, deployable software.

• Build and maintain full stack applications using Python backend and React frontend
• Design and implement APIs, services, and orchestration layers for product workflows and internal tooling
• Develop testing harnesses, simulation frameworks, and validation tools for complex workflows and agent-based systems
• Create reusable frameworks for workflow execution, automated testing, sandboxed environments, synthetic data generation, and regression validation
• Build developer-facing tools to improve engineering velocity, reliability, and repeatability
• Integrate external APIs, services, and third-party tools into internal platforms
• Implement logging, tracing, observability, and error handling across systems
• Collaborate with product, design, and platform teams to scale experimental ideas into technical solutions
• Define engineering standards for reliability, maintainability, and deployment readiness

Required Qualifications:

• Hands-on experience building production systems with Python
• Hands-on experience building modern frontend applications with React
• Experience designing and consuming REST APIs and/or async service architectures
• Demonstrated harness engineering experience: building tools for testing, validation, simulation, automation, or execution environments
• Comfortable working across application code and engineering infrastructure/tooling
• Strong understanding of software design, debugging, and performance optimization
• Experience with relational databases such as PostgreSQL or MySQL
• Familiarity with CI/CD pipelines, Git workflows, and deployment practices
• Ability to work independently, move quickly, and make sound engineering tradeoffs

Preferred Qualifications:

• Experience with workflow orchestration, agent-based systems, or automation pipelines
• Experience with Docker, cloud infrastructure, and containerized environments
• Familiarity with background job systems, queues, and event-driven architectures
• Experience building internal platforms, QA tooling, evaluation frameworks, or developer productivity tools
• Exposure to LLM/AI workflow orchestration, RPA, or test automation systems
• Experience with observability tools, telemetry, and production monitoring

No specific schedule, benefits, or location details provided in the job posting.