Senior Full-Stack Developer — Authentication / API / Minimal Web App

Senior Full-Stack Developer — Authentication / API / Minimal Web App We are looking for an experienced individual full-stack developer to build the first functional version of an existing web product. The product, interface and visual experience have already been designed. This is not a dashboard, SaaS template or open-ended UX project. The interface is intentionally minimal and highly considered. The work is primarily technical implementation. Scope The existing web experience needs to support: ● Secure account establishment and sign-in ● Persistent authenticated user state ● Creation and storage of a unique user identifier ● Backend and database implementation ● Basic account and session management ● Secure authentication handoff between the web application and a separately developed Flutter iOS app ● API/endpoints required by the app to verify authenticated state ● Web-side support for Universal Links / deep linking ● Session expiry, logout and invalid-access states ● Production deployment and configuration ● Clean, maintainable architecture that can expand later A broader contribution model has already been designed and will be represented within V1, but it will not be financially operational in this phase. No payment processing, contribution ledger or allocation system is required in the initial build. iOS Integration The accompanying iOS application is being developed separately. You will need to communicate directly with the Flutter developer to establish a simple and secure authentication/API contract between the two systems. You are not expected to develop the iOS application. Important The product design is already resolved. We are not looking for someone to redesign the interface, introduce conventional dashboards, add unnecessary UI or turn the product into a standard SaaS application. Accurate implementation of the existing design and attention to subtle interaction details are important. We value simple, production-safe architecture over unnecessary infrastructure or premature scaling. All source code, infrastructure, database, hosting and production services must remain within client-owned accounts. Ideal Experience Strong experience with: ● Modern full-stack web development ● Authentication and secure session architecture ● Relational databases ● API design ● Web-to-mobile authentication flows ● Universal Links / deep linking ● Production deployment ● Application security fundamentals Experience with Stripe or payment architecture is useful for future phases, but payment implementation is not required for V1. Individual developers preferred. No agencies. When Applying Please include: 1. 2–3 relevant web applications you personally built 2. Your specific role on each 3. An example involving authentication and persistent user accounts 4. Any experience connecting a web account system with an iOS or Android application 5. Your preferred technical stack for this project and why 6. Your hourly rate and current availability 7. In 3–5 sentences, how you would structure authentication between a web application and a separately developed iOS app Please begin your application with: XXXIII Further design and functional documentation will be provided to shortlisted developers.