I built a Harry Potter Quiz site with AI-generated Hogwarts Letters - now it's getting traction!

Hey IndieHackers! 👋                                                                              

  I want to share my journey building https://harry-potter-house-quiz.org - a fan site that helps   

  Potterheads discover their Hogwarts house, and recently added AI-powered features that have been a

   game changer.                                                                                    

  What is it?                                                                                       

  A collection of Harry Potter personality quizzes and AI-powered magical experiences:              

  - 🎩 Sorting Hat Quiz - Discover your Hogwarts house (with an AI chat mode that feels like talking

   to the actual Sorting Hat!)                                                                      

  - 🦌 Patronus Quiz - Find your magical guardian animal                                            

  - 👤 Character Quiz - Which HP character are you most like?                                       

  - ✉️ Hogwarts Letter Generator - Get a personalized AI-generated acceptance letter (FREE!)        

  - 🖼️ House Portrait - AI face-swap to see yourself in Hogwarts robes                              

  - ✨ Summon Patronus - See yourself casting your Patronus in the dark forest                      

  Tech Stack                                                                                        

  - Framework: Next.js 14 (App Router)                                                              

  - Database: PostgreSQL + Drizzle ORM                                                              

  - Auth: NextAuth.js v5                                                                            

  - AI: OpenAI, Replicate (for image generation)                                                    

  - Payments: Stripe (for premium AI features)                                                      

  - Hosting: Vercel                                                                                 

  - i18n: 8 languages (en, zh, es, de, nl, it, ar, ja)                                              

  What's working well                                                                               

  1. Free tier drives virality - The Hogwarts Letter used to require login + credits. I made it     

  completely free with rate limiting (3/day per IP, then CAPTCHA). Sharing exploded because people  

  love showing off their personalized letters.                                                      

  2. Social sharing is crucial - Spent way too long debugging why shared letters weren't showing on 

  Twitter/Facebook. Lesson learned: social crawlers don't follow redirects, and Vercel OG can't     

  fetch external images reliably. Solution: use direct image URLs.                                  

  3. Localization pays off - Supporting 8 languages brought in traffic from unexpected markets.     

  Chinese and Spanish users are very engaged.                                                       

  4. AI features convert - The free quiz brings users in, AI image generation (portraits, patronus) 

  converts them to paying customers.                                                                

  Lessons Learned                                                                                   

  - Start free, monetize later - Removing friction (login, credits) for the core feature            

  dramatically increased engagement                                                                 

  - Social sharing is technical - OG meta tags, image dimensions (1200x630), no redirects - it's    

  more complex than it seems                                                                        

  - Fan communities are passionate - Harry Potter fans LOVE sharing their results. Build for        

  shareability.                                                                                     

  What's next                                                                                       

  - More AI experiences (Marauder's Map with your location?)                                        

  - Mobile app                                                                                      

  - Expanding to other fandoms                                                                      

  Would love to hear your thoughts! Anyone else building in the fan/entertainment space?