Senior Full-Stack TypeScript Engineer for Mobile-First Membership Learning App

We are rebuilding an English learning membership platform into one production mobile-first web app. The business has 700+ paying members and a hard September 1 launch target. A student-facing prototype already exists in React/Lovable, but the production system still needs to be built properly: login, product access, scheduled lessons from a database, protected media, student homework/comment submissions, admin workflows, Kartra subscriber sync, scheduling, notifications, testing, and deployment. You will work with a fractional CTO who owns architecture, scope, code review, and project management. This is not a prototype role. We need someone who can build reliable production software, communicate clearly, and surface risks early. Expected engagement: $2,500-$3,000/month, starting early July, with expected availability of 20-30 hours/week through the September 1 launch. Remote is fine, but meaningful overlap with Europe/Prague working hours and strong responsiveness on business days are required. V1 SCOPE V1 is focused on the core member homework product: - member login and session handling - product-based access control - Kartra subscriber/access sync into the app database - scheduled daily homework lessons stored in buckets - weekday audio lessons - weekend video lessons - admin upload/publishing workflow for audio and video lessons - existing audio player connected to real lesson data - protected audio/video access behind login - lesson archive - student homework/comment submissions - daily release scheduler at 19:00 Europe/Prague - operational email notifications - first-time onboarding video surface - admin subscriber lookup and access audit - support/admin tools for publishing, subscriber questions, failed jobs, and access issues - staging and production deployment flow - practical automated tests for critical paths EXISTING SYSTEMS - Kartra remains the V1 checkout, billing, subscriber, and marketing email source. - The app should mirror Kartra access into its own database. - The frontend should not call Kartra directly. - Byta currently holds audio/video material and may be used as source/archive. - Circle is used for Community Area in V2 PREFERRED TECHNICAL DIRECTION Exact choices will be finalized with the CTO, but the expected direction is: - TypeScript - React mobile-first web app / PWA - Vite or similar frontend tooling (no NextJS app) - Node.js backend: Fastify, NestJS or comparable - Postgres - REST/JSON APIs with validation - queue/scheduler for background jobs - GitHub Actions + CI/CD - staging and production environments - private media storage or protected media URLs You must have strong production judgment around auth, access control, data modeling, background jobs, and deployment. YOU ARE A GOOD FIT IF - you have built production membership, subscription, SaaS, or learning platforms - you understand authentication and role/access separation - you can model products, users, entitlements, lessons, and audit logs cleanly - you know how to process webhooks idempotently - you can build mobile-first React UI from wireframes - you can work async with written updates and daily Slack presence on business days - you ask precise questions instead of making hidden assumptions - you can explain tradeoffs simply in non-technical language - you flag bad news early NOT A GOOD FIT IF - you mostly build prototypes without production ownership - you want to put business rules in the frontend - you struggle with clear and proactive communication - you would call Kartra/Circle directly from the browser - you treat protected paid media as simple public links - you avoid tests, staging, or deployment discipline - you over-engineer microservices for a small first production team - you need every task specified down to implementation detail Please skip the generic cover letter. Share your GitHub, portfolio, or website, and answer the questions below directly. Keep answers concise and specific.