Next.js + Supabase developer — interactive self-knowledge web app (40-day program, full spec ready)

I'm looking for a developer to build Origen Digital — the flagship product of Cima (soycima.co), a personal development startup based in Colombia. Origen is not a course platform or a content site behind a login. It's a web application: each participant builds a persistent 20-trait self-portrait written in their own words across 40 days and 4 modules. The system stores their responses, surfaces previous answers as read-only context in later screens, and displays a cumulative portrait that grows module by module. The architecture, data model, and UX logic are fully documented. You won't be defining what to build — you'll be implementing a detailed spec. What you'll build – M0 (free entry product): audio player + 15-question workbook + email capture connected to Kit (ConvertKit) – 4 modules with question screens, text input fields saved to Supabase, and persistent portrait display – 25 audio files with click-to-play behavior (no autoplay, with one defined exception) – Cumulative self-portrait: 20 fields visible as a persistent screen, accessible from the product menu at any time – Previous responses surfaced as read-only context in later screens – Stripe payment flow + authenticated access to the product – Kit integration: automated email sequences triggered post-M0 and post-purchase – Closing ritual screen (Declaración Cima) — not a downloadable PDF, a screen – Responsive design — mobile first Stack – Next.js (frontend + server logic) – Supabase (database + authentication + Row Level Security) – Stripe (payments + webhooks) – Kit / ConvertKit (email automation integration) This stack is defined. Please don't propose alternatives. What's NOT in V1 – On-the-fly PDF generation – Granular screen-by-screen blocking logic (one exception already defined) – Complex Make automations – Community or social features Timeline – Start: as soon as possible (June 2026) – Deadline: product live by October 3, 2026 – Build window: 10 weeks Documentation available Everything you need to scope and build is documented: – Technical Briefing (120+ Supabase fields, architectural principles, full navigation flow) – Screen-by-screen Indexed Living Documents (M0 through Epilogue) – Complete participant journey document Documentation is shared after NDA is signed. What I'm looking for – Strong Next.js experience — dynamic routes, server-side rendering, stateful apps – Strong Supabase experience — relational schema design, auth, RLS, real-time queries – Stripe integration experience — payments, webhooks, post-purchase session management – Portfolio showing web applications with persistent user state — not just content sites or landing pages – Ability to read a detailed technical brief and implement it without constant explanation – Clean UI sensibility — the product handles emotionally significant content; screens must be simple, readable, and distraction-free Conditions – Fixed-scope project — quoted against the V1 spec – Git repository under my ownership from the first commit – All platform accounts must be registered in my name – Weekly progress reports + at least one meeting per week – NDA required before sharing full documentation – Payment by milestones: start / M0 + M1 delivery / full delivery / testing and launch To apply Please include: – 2-3 examples of web applications you've built with Next.js + Supabase that involve persistent user state (not content sites) – Your availability to start and your estimated timeline for this scope – Your rate (fixed project quote or hourly — both are fine) – A brief note on how you'd approach the Supabase schema for a product like this Applications without portfolio examples of stateful web apps will not be reviewed.