Your AI-built site looks custom. Then the Book button opens a Calendly page 🗿
The booking flow is the part customers touch most, and everyone outsources it to an ugly embed
Something kept bugging me while I watched people vibe-code sites for service businesses.
They'd spend a weekend getting the landing page perfect in Lovable or v0: typography, photos, the whole brand. Then they'd hit booking and do one of two things:
Paste in a Calendly link or an Acuity iframe. Different font, different colours, and it's the one screen where the customer actually pays.
Ask the AI to build booking itself. It does, sort of: a hard-coded list of times, bookings saved as rows, no slot hold, no payment. Fine for a demo, a liability in production, and now it's yours to maintain.
The underlying mistake is thinking booking is a calendar. A padel club books courts on a grid. A podcast studio books a room, a setup and add-ons like editing. A barber books a person. A car rental books days. Calendly gives all four the same month view.
That's the gap Opencals was built for: booking and commerce as an API, so the front end can be whatever the business needs. One podcast studio owner built his whole booking flow into his own site on the API in just over a weekend. What changed this week is that you don't need to be that owner: the front end can now be vibe-coded.
What we shipped
Lovable: a custom connector (Advanced auth, two headers) plus two knowledge files: a 36k-char endpoint reference and a 14k-char playbook that makes Lovable choose the flow by business type before it touches the design.
v0: nothing new. v0 supports Agent Skills, so the Opencals skills we open-sourced last week work straight from skills.sh
Base44: a backend function plus two workspace skills. Base44's API integrations send fixed headers and our carts need a per-visitor ID, so a proxy function it is.
Why I think this matters
For years a custom booking experience meant hiring a developer. AI builders just made the front end nearly free. The only thing standing between a four-chair barbershop and a booking flow that actually looks like them was the engine underneath, and that's the one part you really shouldn't generate.
Guides: https://opencals.com/blog/build-booking-website-with-ai
