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# Senior Full Stack Engineer

- **Company:** FLEXAI LLC
- **Location:** San Jose, CA, United States
- **Experience:** Expert
- **Contract:** Permanent contract
- **Skills:** Application Programming Interfaces (APIs), Continuous Integration, Software Debugging, Programming Tools, Design of User Interfaces, Human-Computer Interaction, Python (Programming Language), Node.Js, Platform as a Service (PAAS), Systems Integration, Scripting, ReactJS, AI Coding Agents, Backend, Fastapi, Kubernetes, Front End Software Development, Api Design, Marketplace, Multiplatform, Web Api
- **Published:** November 2, 2026
- **Apply:** https://www.careerbuilder.com/job-details/senior-full-stack-engineer-san-jose-ca--b29fdc93-5f96-40da-a378-32352f464cc5

## About the Role

Licensing, Application Programming Interface (API), Data Modeling, Platform as a Service (PaaS), User Interface/Experience (UI/UX), Multiplatform/Cross-Platform, Billing, Programming Tools, Python Programming/Scripting Language, Node.js, * 5+ years of experience with a Bachelor's and/or Master's degree building Full Stack applications

 * Strong skills in:
*

 + Frontend: React (modern stack)
 + Backend: Python (FastAPI or similar) or Node.js
 * Experience designing and working with APIs
 * Comfortable with data models, async workflows, and scalable systems
 * Ability to operate independently and move fast with high ownership
 * Strong communication and collaboration skills
 * Experience working in startup environments
 * Comfortable leveraging AI coding tools and agents to move faster

Nice to Have

 * Experience with cloud platforms, developer tools, or compute systems
 * Familiarity with Kubernetes, CI/CD, and observability
 * Exposure to billing, licensing, or marketplace systems

## Description

FlexAI is looking for a Senior Full Stack Engineer who can build end-to-end features across our PaaS platform - including frontend UI layers, backend APIs, data models, and integrations with compute and infrastructure systems. You will work on developer modules Admin modules, Marketplace, and Licensing, shaping the user experience and backend logic., * Build and ship end-to-end features across our platform (developer tools, marketplace, billing, admin)

 * Develop high-performance UIs using React
 * Design and implement APIs and backend services using Python (FastAPI) and/or Node.js
 * Define clean, scalable contracts between frontend and backend
 * Work on data-intensive workflows (jobs, compute orchestration, resource management)
 * Collaborate with platform and infrastructure teams to build reliable systems
 * Debug and optimize across the stack - from UI to backend performance
 * Own features end-to-end: design, build, ship, and operate