Trevor BehnkeDayChart — Full-Stack SaaS MVP
24-Hour Scheduling Visualization Web Application with Metrics & AI Suggestions
Sole Architect & Engineer•2023
Next.jsTypeScriptPrismaZustandStripeClerkPostgreSQLMUITailwindD3.jsOpenAI API
Background
Inspired by research on how writing down even small daily events can improve time management and reduce wasted hours, I set out to create a tool that makes a full day visible at a glance. I wanted a way to see an entire 24-hour schedule laid out like an analog clock — where each slice of the donut represents the real proportion of time spent. Existing solutions didn’t provide this, so I built DayChart as a full-stack SaaS web app. Beyond visualization, the app includes metrics and insights: free time analysis, category breakdowns, and AI-powered suggestions to help users balance their routines with exercise, self-care, or social time.
Contribution
- Solely designed, architected, and engineered the product from concept through deployment
- Implemented secure auth (Clerk) and subscription tiers (Stripe) with full CRUD functionality
- Built the core 24-hour donut chart visualization using D3.js for precise, time-scaled slices
- Developed a dashboard with metrics tracking free time, category distribution, and weekly summaries
- Integrated AI prompts via the OpenAI API to generate personalized scheduling suggestions
- Optimized performance and user experience with state management (Zustand), component libraries, and responsive UI patterns
- Deployed on Vercel with reliable CI/CD, ensuring fast, stable production performance
Learned
- How to take a product idea from spark → design → fully functional SaaS platform
- Strengthened full-stack skills: database design, API development, and UI architecture working seamlessly together
- Gained deeper expertise with D3.js by building a custom visualization tied to real-world time intervals
- Learned to balance technical complexity with UX simplicity, creating a tool that feels refined without being overwhelming
- Experienced the value of AI integration not just as a novelty, but as a feature that adds meaningful user benefit
- Built appreciation for the discipline required to operate a SaaS: auth, billing, reliability, and performance all matter as much as the core feature