Senior Full-Stack Developer (Marketplace / Platform Completion Specialist)

We are looking for a highly experienced senior full-stack developer to take over and continue building an existing custom web platform. This is a takeover + completion role, not a ground-up build. We need someone who can understand a complex system quickly, interpret product vision accurately, and deliver fully functional features the first time with minimal back-and-forth. About the role We are building a multi-user digital platform ecosystem with: role-based user dashboards content and discovery systems saved content / collections functionality marketplace-style interactions between users search and filtering systems structured user profiles and matching logic A significant portion of the platform is already built. The current challenge is not design — it is true functionality, system completion, and reliability. What you will do Take over an existing codebase from a previous developer Understand the full platform quickly without extensive hand-holding Identify what is incomplete, broken, or not functioning correctly Fix and complete core platform functionality Improve search, filtering, and marketplace discovery logic Ensure all features actually work end-to-end (not just UI) Double-check your own work before submission Build with stability, accuracy, and production readiness in mind Key focus areas Marketplace functionality between multiple user types Search and filtering system (accuracy + relevance are critical) Role-based dashboards and permissions User discovery / matching logic Content feed and engagement features Saved content / collections system Messaging or interaction systems between users Admin/owner control features Must-have experience We are ONLY looking for senior-level developers with proven experience in: Full-stack web application development Marketplace platforms OR multi-user systems Search / filtering / discovery systems Working inside existing codebases (not just building from scratch) Backend + frontend integration Database design and structured data systems Debugging and completing incomplete platforms Ideal candidate You are a strong fit if you: Can quickly understand large, complex platforms Have built or improved marketplaces, SaaS tools, or social platforms Think in systems and workflows, not just individual pages Take ownership of functionality (not just code delivery) Test and verify your own work before submitting Prefer fixing and improving over rebuilding from scratch Can translate non-technical vision into real working systems Important expectations This is NOT a simple website build This is NOT a design-focused project This is NOT a rebuild from scratch You must be comfortable inheriting existing work You must ensure features are fully functional before delivery Accuracy and reliability are more important than speed alone We are looking for someone who can own the functionality layer of a complex platform. Please include in your proposal Examples of marketplace, SaaS, or multi-user platforms you have built or improved Examples of projects where you inherited an existing codebase How you approach understanding a large unfamiliar system How you ensure your work is fully functional before delivery Your experience with search, filtering, or discovery systems Your availability for the next 4–6 weeks Bonus (strongly preferred) Experience improving search or ranking systems Experience with marketplace discovery flows Strong backend architecture experience Startup experience working under fast timelines Strong attention to detail and QA mindset