Full-Stack Engineer for Node.js, React, Auth, Payments, and Admin or White-Label Features

We are looking for an experienced Full-Stack Engineer to extend an existing product across both the backend and frontend while following our current architecture and development standards. Our stack includes Node.js, Vite, React, TypeScript, PostgreSQL or an existing database, and Vercel or a similar deployment platform. Your work will include strengthening and extending our authentication system with sessions, roles, and permissions, adding a new subscription tier to our existing payment and billing flow, and building either an admin panel or a white-label MVP. The final scope for the last feature will be confirmed before development begins. We expect you to work within our existing repository, coding patterns, and database schema rather than introducing new architectures or restructuring what is already working. Deliverables include working authentication updates with tests, a new payment plan integrated into our existing billing logic with consistent pricing, upgrades, downgrades, and invoicing, an admin panel or white-label MVP, fully typed TypeScript code without using any, no dead code, zero console errors, reversible migrations, and feature-based pull requests with small, self-reviewed commits. When applying, please share a repository or live project you personally developed, preferably one involving authentication or billing, your typical turnaround time for a moderately complex backend feature with tests, your experience with payment platforms such as Stripe or Paddle, and your availability in hours per week on a consistent schedule.