The Last Slot

An appointment is more than a slot on a calendar: staff rosters, buffers, resources, deposits and changes all affect whether it can be booked. A small service business needs those rules to agree across public booking, the front desk and checkout.

Bywater’s original product, documented in the BookingOS repository. The scope spans the multi-staff calendar, availability engine, client records, point of sale, reports, messaging and tenant boundaries. The product is The Last Slot; BookingOS is its source repository name.

AI-assisted implementation is made reviewable through explicit feature maps, acceptance checks and known-limitations notes. The useful evidence is the behaviour and its tests: conflicts, money calculations, cross-tenant references and reminder retries. Provider mocks make development possible without sending messages or charging a card.

Availability is a pure calculation covering rosters, exceptions, buffers and daylight saving. Money and inventory changes use database transactions. Email, SMS and payment adapters default to mocks; live Stripe behaviour is gated separately. Tenant scope is derived from the signed-in session rather than trusted from form input.

The calendar screenshot shows the implemented product with demo data. The source includes booking, checkout, reminder jobs and tests for tenant isolation. The repository’s acceptance checklist records earlier local verification, but it is not a fresh production audit. No verified public demo is linked here.

This is presented as a product prototype, not a claim of paying customers or production payment processing. Real provider credentials and end-to-end card-flow verification are separate release work. Screenshots and mock-provider results do not establish a live commercial service.