TeeTimeBuddy: Golf Trip Planning for Crews

Golf trips usually fail before anyone books a tee time. Availability lives in a group chat, votes are vague, and one organizer has to chase the crew until a date finally sticks. By the time everyone agrees, the best windows are gone.

The coordination layer is the hard part. Finding when 6-7 people are actually free, getting buy-in on a destination, and splitting costs fairly — all of this happens in 47-message group chats that nobody wants to scroll through.

TeeTimeBuddy gives the crew one shared planning surface. Members mark availability, vote in / maybe / out on proposed trips, chat in context, and keep the current plan visible without digging through messages.

• Shared availability grid for the crew — tap to cycle Free / Maybe / Busy across a 90-day horizon.
• Smart trip windows — the system cross-references everyone's calendar and surfaces the best stretches.
• Trip proposals with clear voting states — I'm in, Maybe, Out — so the captain knows exactly where consensus stands.
• Realtime crew chat tied to the plan, not lost in a separate thread.
• Expense tracking with automatic split calculations and settlement summaries — who owes whom, settled at the 19th.

TeeTimeBuddy is built on TanStack Start with React 19, using Supabase for auth, Postgres, and realtime subscriptions. The goal was a responsive, collaborative experience that feels instant even when 7 crew members are updating availability at the same time.

• Realtime-First: Three tables (availability, chat, votes) use Supabase Realtime so updates propagate instantly across all connected clients.
• Row-Level Security: All data is scoped by crew membership. You only see crews you belong to, and RLS policies enforce this at the database layer.
• Smart Window Algorithm: The trip-window picker cross-references every member's availability grid to surface stretches where the most people are free — even when 6 calendars look impossible, it finds the gap.
• Expense Settlement Math: The tab tracks who paid what, calculates per-person share, and outputs a minimal settlement graph (who owes whom, how much).

The core loop is simple: a captain creates a crew, shares an invite link, members mark their availability, the group sees the best windows, and the captain turns consensus into a proposed trip. Once quorum votes in, the trip locks and coordination shifts to logistics.

TeeTimeBuddy is an independent MVP/demo product focusing purely on pre-booking coordination. It does not handle live tee-time inventory, payments, or on-course GPS. The next phase includes deployment freshness, RLS policy audits, secure invite tokens, guest responses, server-side domain workflows, observability, notifications, and shareable planning pages.

Present as a credible build demonstrating realtime coordination patterns, not a scaled commercial platform.