Justin Lite – AI Reflective Journaling Application

AI Reflective Journaling Application

AI-powered reflective journaling platform designed for behavioral change and addiction recovery. Unlike typical chatbots that rush to provide solutions, Justin Lite asks thoughtful questions to foster self-reflection. Full-stack TypeScript application with subscription billing, privacy-first architecture, and context-aware conversation management.

What It Solves:
- Reflective AI that prioritizes questions over answers, creating space for user insight
- Pattern recognition across conversations to identify recurring themes and "drift moments"
- Rolling conversation summaries that preserve context without storing full transcripts
- Memory extraction learning user patterns (triggers, goals, struggles) while respecting privacy
- Subscription-based access with 7-day free trial via Stripe integration
- Optimistic UI updates for instant chat response feel

Tech Stack:
Backend: Node.js, Express.js 5.1, TypeScript 5.8, Supabase (PostgreSQL + Auth), OpenAI API (GPT-4o), Stripe, Zod validation
Frontend: React 19, TypeScript, Vite, React Router 6, Zustand (5 stores), Tailwind CSS, Supabase JS Client

Key Technical Wins:
- Token cost optimization: rolling summaries + message windowing (last ~20 messages) reduced OpenAI costs while preserving context
- Extensive prompt engineering with "doctrine" system preventing AI behavioral drift
- Stripe Payment Links with post-checkout signup flow (no email verification friction)
- Structured error handling with base AppError class and global error handler
- Rate limiting per authenticated user (30 req/min) preventing abuse
- Authorization enforced at conversation level vs. message level (simpler RLS policies)
- Custom logging middleware tracking method, path, status, duration, and user ID per request

Scale:
Production SaaS application with authentication, subscription management, AI conversation engine, and privacy-first data architecture. Active users in addiction recovery community. ``` --- **SEO Meta Description** (160 characters): ``` AI reflective journaling app built with React, TypeScript, Node.js, and OpenAI API. Subscription SaaS with Stripe billing, privacy-first architecture, and conversation management. ``` **SEO Title:** ``` Justin Lite | AI Journaling App - TypeScript Full-Stack Project ``` **Focus Keyword:** ``` Full Stack TypeScript Developer ``` **Excerpt:** ``` AI-powered reflective journaling platform for behavioral change. Full-stack TypeScript application featuring OpenAI integration, Stripe subscription billing, optimized conversation context management, and privacy-first architecture. Built with React 19, Node.js, Express, and Supabase.