Description: We are seeking an experienced Next.js Developer to complete a membership-based web application. The project is mid-build and requires an immediate, capable developer who can finish and extend the platform to meet business-grade requirements. Key Responsibilities: Integrate Memberstack for membership management, user authentication, and subscription billing. Implement server-side IP-based access control within the Next.js framework. Integrate SAML Single Sign-On (SSO) for enterprise clients using WorkOS (or a similar provider) and connect it to the Memberstack user system. Develop and secure server-side functions for login, IP verification, and webhook handling (subscriptions, SSO events). Ensure clean, scalable, and secure code practices. Coordinate with our internal team to bring the project to production-ready completion. Technical Requirements: Proven expertise in Next.js and React.js. Experience integrating Memberstack or similar membership platforms (e.g., Auth0, Clerk.dev). Strong knowledge of server-side functions in Next.js (e.g., getServerSideProps, API routes). Ability to implement IP-based access restrictions using server-side logic. Experience with SAML SSO flows and WorkOS, Auth0, or equivalent. Familiarity with Stripe for subscription billing is a plus. Strong understanding of authentication, authorization, and security principles. Comfortable with PostgreSQL or MongoDB for user and access management. Other Requirements: Available for immediate start. Able to deliver high-quality, production-ready code within agreed deadlines. Excellent communication and reliability. Contract Type: Freelance (with potential for ongoing project work). Location: Remote (UK hours preferred but flexible). How to Apply: Please provide: Your portfolio or examples of similar projects. A brief overview of your approach to handling IP access control and SAML in a Next.js environment. Your hourly or project-based rate and availability.