Barbería Costanera — a one-chair barbershop in Encarnación, Paraguay, where "Can I book with you?" becomes "You're booked" in under a minute, while the owner keeps cutting. It started with a real barber. Before writing a single prompt, I interviewed a barber in my city. His day: cutting hair with one hand and answering WhatsApp with the other. Clients asking "do you have time tomorrow?", no-shows he can't refill, time spent on messages instead of work. Barbería Costanera and its owner, Ramón, are fictional, but every rule in the app comes from that conversation. Built for this city, not for any city → Midday siesta closure: the app never offers those hours. → Clients cross the bridge from Posadas, Argentina, and traffic is unpredictable: one tap tells the barber "I'm 10 minutes late". → Prices in guaraníes. Every screen and every message in English and Spanish. → Friday afternoons and Saturdays fill up; weekday mornings don't. The app knows it. For the client: ask like on WhatsApp Type "Can I book for tomorrow?" in the chat on the home page and the app answers instantly with real free times you can tap. Pick one, add your name and WhatsApp, and you're booked. No account, no password. Then: add it to Google or Apple Calendar with reminders, reconfirm, reschedule, cancel, or warn you're running late, all from one private link. For the owner: he only handles the exceptions → His whole day on one screen, live: who's next, who confirmed, who's late. → A cancellation is offered automatically to the waitlist, with a 30-minute hold that passes to the next person if unclaimed. → Reminders 24 h before, reconfirmation 3 h before, a thank-you after the cut and a rebook nudge 3 weeks later, all generated on their own, in each client's language. → Clients with 2+ no-shows (and Saturday bookings) leave a small deposit. Free cancellation up to 3 hours before. → Walk-ins in two taps, blocked hours, client history, and an impact card showing time and bookings saved, with every assumption visible. Judges: try both sides in 60 seconds Book from the chat on the home page. Open the Owner Desk and tap "Enter as Ramón" (no password). Use the demo time machine (+24 h) to watch the reminders write themselves. Security note: the Owner Desk is intentionally open in this public demo so judges can test it, and all data resets nightly. In production, owner access sits behind a real login with role checks; client and booking data are already protected with row-level security, rate limits and no personal data in public responses. Under the hood Lovable + Supabase. Real-time availability with a final server-side check (no double bookings, enforced in the database). When the day strip took 8 seconds to load, I rebuilt it into a single query: 1.4 seconds. The craft of cutting hair can't be automated. Everything around it can. Demo: https://barberia-costanera.lovable.app (https://barberia-costanera.lovable.app)Lovable project: https://lovable.dev/projects/e6eddd09-413f-485e-beba-c9bfa4485f78 LinkedIn: https://www.linkedin.com/feed/update/urn:li:activity:7511506507222634496/?originTrackingId=%2FdVHr5ABQUGhDOs8FK%2BI9w%3D%3D If you run a small business, what's the message you answer 20 times a day? #lovablechallenge

Marco Gonzalez

Passionate about technology