Senior Fullstack Engineer

Foresite•Overland Park, KS

11h

About The Position

Foresite is seeking a product-minded Senior Fullstack Engineer with a mastery of modern front-end architectures to help build and scale our multi-tenant SaaS platform. As a foundational member of our engineering team, you won’t just write code—you will architect the "humans-first" interfaces that make complex cybersecurity data intuitive and actionable. In this role, you’ll be working on our multi-tenant SaaS platform built with modern web technologies. Your primary focus will be leading the evolution of our front-end ecosystem while maintaining a strong, lateral grip on our backend services. You will ensure our platform remains performant, accessible, and maintainable as we scale.

Requirements

5+ years of professional experience in Full Stack development, with a clear specialization in front-end architecture for complex B2B SaaS or Cybersecurity platforms.
Deeply proficient in React 18/19 and TypeScript.
Comfortable with React Router v7 and modern routing patterns.
Build secure web applications by default. Understand and mitigate common vulnerabilities such as XSS, CSRF, and injection attacks, and know how they apply in modern React and TypeScript apps.
Comfortable designing schemas, writing queries, and reasoning about performance across PostgreSQL and Firestore.
Feel at home with modern ORMs and use runtime validation to enforce data integrity at system boundaries.
Experience with multi-tenant architectures and implementing robust RBAC/ABAC models to enforce strict data isolation.
Write tests as part of the job, not as an afterthought. Proficient with Vitest and Testing Library for unit and integration coverage, and Playwright for critical E2E flows.
Care about developer experience. Comfortable with CI/CD pipelines, Git, and modern workflows like Stacked PRs. Embrace AI-assisted development tools to ship faster without sacrificing quality.
Comfortable on both sides of a system boundary — consuming third-party APIs on the frontend and writing the backend glue that connects them. Understand API contracts, webhook reliability, and data consistency across services.

Nice To Haves

You have a background in Cybersecurity, understanding the unique UI/UX and security challenges of the industry.
You have a "Security First" approach to coding, always thinking about the OWASP Top 10.

Responsibilities

Architect and build front-end features for our multi-tenant SaaS platform using React.js and TypeScript
Work across the full stack, owning backend integrations and data access patterns end-to-end
Build and maintain a shared component library that scales consistently across our client base
Partner closely with product, design, and backend engineers to ship polished, production-ready features
Integrate with PostgreSQL and NoSQL data stores through clean, well-structured backend service layers
Design, consume, and extend RESTful APIs that power our platform’s core workflows
Champion code quality through thorough reviews and consistent enforcement of engineering standards
Own your deployments—debugging, performance tuning, and keeping production healthy
Drive architectural decisions and contribute to engineering roadmap planning
Mentor junior and mid-level engineers through pairing, feedback, and code review
Identify and address performance bottlenecks across the front-end and API layers
Apply security-conscious development practices, particularly around auth, RBAC, and data isolation in a multi-tenant context
Engage actively in Agile ceremonies including sprint planning, standups, reviews, and retrospectives
Document what you build and contribute to a culture of knowledge sharing across the team