Senior Full-Stack SaaS Engineer

Senior Full-Stack SaaS Engineer React, Next.js, Node.js | Existing MVP to Production Overview We are building a secure, workflow-driven SaaS platform that manages digital records, collaboration, document generation, user verification, and business automation. A high-fidelity interactive prototype has already been built in React. We are looking for an experienced senior full-stack engineer to evaluate the existing prototype, then lead development of a secure, production-ready application. The platform serves a specialized professional industry. This is not a marketing website. It is a multi-workflow business application with authentication, permissions, dashboards, approvals, document generation, and subscription billing. Phase 1 — Paid Architecture Review The first phase of this engagement is a paid architecture review and technical assessment of the existing prototype. You will: ● Review the current React prototype in detail ● Identify what should be reused, refactored, or rebuilt ● Recommend the production architecture ● Deliver a written technical assessment and implementation plan Successful completion of Phase 1 leads to the full development contract. Full Development Responsibilities ● Implement the recommended backend architecture ● Build secure REST API and database layer ● User authentication and multi-factor authentication ● Organization and team accounts with role-based permissions ● User verification workflows ● File and document storage ● PDF document generation ● Subscription billing via Stripe ● Deployment to Vercel, AWS, or Google Cloud ● Testing, documentation, and CI/CD pipeline ● Write clean, maintainable, well-documented code Required Skills ● React and Next.js ● TypeScript ● Node.js ● PostgreSQL ● Supabase or Firebase ● Stripe — subscriptions and payments ● Authentication — OAuth, JWT, MFA ● SaaS architecture and multi-tenancy ● Production deployment — Vercel, AWS, or Google Cloud ● GitHub and version control Preferred Experience ● SaaS platforms, CRM systems, or workflow software ● FinTech, LegalTech, or compliance applications ● Twilio SMS, SendGrid, and document generation services What We Are Looking For We are not looking for the lowest bid. We are looking for a senior engineer who: ● Has built and shipped real SaaS products ● Thinks about architecture, security, and scalability — not just features ● Can work independently from a well-documented prototype ● Communicates clearly and documents their work This project has the potential to become a long-term opportunity. We are looking for someone interested in becoming the lead technical engineer as the platform grows. Please Include in Your Application ● Three SaaS applications you have built — your specific role in each ● Links to live products ● Your recommended backend architecture for this type of application ● Estimated timeline and approach for the architecture review phase Describe a SaaS architecture you designed that scaled successfully. What would you do differently today? Applications without live SaaS examples will not be considered. Generic proposals will not be considered. Please begin your proposal with the words "SaaS Architect" so I know you have read the full job description. Confidentiality Additional project details — including the product name, prototype access, and full technical documentation — will be shared with selected candidates after execution of a Non-Disclosure Agreement.