Senior Full-Stack / Platform Engineer for AI SaaS Product

About the Position

We’re looking for a part-time full-stack engineer to help improve the security, performance, scalability, and maintainability of an already working AI product in production with paid users. The product is live, complex, and growing. We need someone who can step into an existing codebase, understand it quickly, and make it more robust without breaking what already works.

Responsibilities6

• Audit and improve system architecture
• Strengthen security across auth, APIs, validation, file handling, and production workflows
• Improve frontend, backend, database, and background job performance
• Reduce scalability bottlenecks and technical debt
• Refactor critical parts of the codebase safely
• Improve test coverage, reliability, observability, and deployment quality

Requirements5

• 5 years of experience in production web applications
• Strong in TypeScript, React, Next.js, Node.js, and Postgres
• Deep understanding of security, performance, and scalable architecture
• Comfortable working in an existing codebase with technical debt
• Able to make pragmatic improvements in a live product environment