I built Skyler (https://github.com/05sanjaykumar/Skyler-AI), an AI-powered email organizer focused on privacy and semantic search. It was live at skylerinbox.com for a few months before I shut it down due to Google's CASA compliance requirements (100-user OAuth limit without expensive third-party certification).

Built in 42 days solo as a 3rd-year CS student in India.

Tech stack: - Frontend: Next.js, NextAuth, Tailwind, shadcn/ui - Backend: Express (TypeScript), Prisma, Supabase - AI/ML: distilbert (sentiment), all-MiniLM-L6-v2 (semantic search), Groq Llama for summarization - Infrastructure: Docker, Nginx, Hetzner VPS - Privacy-first: Client-side caching with Dexie, minimal server storage

Key challenges: - Gmail OAuth token refresh issues and rate limiting - CASA compliance wall at 100 users (would cost thousands for certification) - Building privacy-first architecture (harder than standard SaaS) - Payment integration (PayPal + Cashfree for India)

Why I shut it down: The compliance overhead (CASA certification, legal costs, ongoing OAuth verification) didn't make sense for a solo MVP. The infrastructure worked great, but the business constraints were brutal.

Demo video: https://youtu.be/ATNYoNt6oBE

All code is open source as a learning resource. Happy to answer questions about the technical decisions or compliance issues I hit!