Shipped production software solo. At 20.

Ivan Shumyk

Now looking for AI engineering work. Economics student; customer experience manager at a golf club.

Read the case Email me

Parity. From spreadsheet chaos to the system the club runs on

The golf club ran tee time bookings on Google Sheets, phone calls, and guesswork. Double bookings, lost reservations, zero visibility into daily capacity. I evaluated every booking solution on the market. Existing tools either charged per-booking commissions eating into margins, or demanded $2,000+ upfront plus ongoing maintenance fees. None fit a single-club operation with specific local needs.

Rather than pitch management on a budget proposal that would die in committee, I built the MVP myself on personal time. AI made it possible to scope, design, and ship a complete system without a traditional dev background. The working software made the case better than any pitch deck could.

Management approved it on the spot. Real guests now book through it every day, and the spreadsheets are gone. Everything below shipped inside a single golf season.

Parity booking widget open on lisnykygolf.com.ua: date selection step with July 2026 calendar over the club's homepage
Booking widget on lisnykygolf.com.ua (opens in a new tab)
Parity admin tee sheet: day counters reading 36 bookings, 32 confirmed, 3 pending, 35 free slots and 42 percent occupancy, above ten-minute slots showing a paid booking, a no-show pair, one waiting on payment, a coach session, per-slot capacity, a blocked interval for greens mowing, and a club tournament
Admin tee sheet · demo club
Live at lisnykygolf.com.ua (opens in a new tab)

What I shipped in 2026

  1. Booking Widget

    Guests book tee times on the club's website themselves: date, time, players, confirmed in under a minute.

  2. Admin Panel

    The staff's daily screen: one live tee sheet on every device, drag-and-drop rescheduling, schedules and prices the club sets itself, and Pro Shop stock imported from the accounting system.

  3. Online Payments

    Guests pay by card as they book. A booking is confirmed only when the bank confirms the money, and an unpaid hold frees the slot on its own.

  4. Lessons & Tournaments

    Coaches moved off their shared Google Calendar: lessons, invoices with payment links, and 10-lesson packages all live in Parity now. Tournament places sell online with a hard cap, starting with the Porsche Golf Cup.

How it holds up

Payments are where the work is: signed gateway callbacks, idempotent writes, a reconciler that settles what the bank confirms late, and refunds that retry until they land.

Sessions are short-lived tokens with rotation; staff access is role-based. Live updates travel over SSE.

More than 500 Vitest specs cover the slot engine, auth, payments, lessons, and tournaments.

Self-hosted on a Linux VPS, so there's no booking-platform commission. Node.js with Express on PostgreSQL via Prisma, React with Vite, WayForPay for payments.

How I work.

I started at a premium golf club as an administrator, handling VIP clients, finances, and daily operations. Today I'm its customer experience manager. When the booking system broke down, I didn't wait for someone else to fix it. That's how Parity started.

I ship production systems end to end: scope the problem, design it, write it with AI, deploy it, and fix what breaks at seven in the morning. Solo, from architecture to the payment edge cases nobody plans for. That's AI-native engineering.

Education
Kyiv-Mohyla Academy,
Economics, 4th year
Working since
Age 14
Handicap
34.2
Off the clock
Skiing & golf

Lisnyky Golf & Villas

  • Customer Experience Manager · Since July 2026
  • Club Administrator · 2025–2026

Operating a premium golf club serving high-net-worth clientele. VIP guest relations, finances, cross-team coordination.

  • Built and run Parity, the system behind the club's bookings, payments, lessons, and tournaments.
  • Inherited a chaotic Google Sheets system. Rebuilt it with proper formulas, automated color-coding scripts, and cross-sheet data imports.
  • Evaluated, configured, and launched KeyCRM. Connected Telegram and Viber channels, built response templates, removed unused modules.
  • Took over Pro Shop operations. Established supplier relationships, managed inventory, coordinated orders.
  • Reconciled financial accounts alongside the CFO in the club's accounting system. Balanced ledgers. Resolved discrepancies.

M.M. Gryshko National Botanical Garden

Seasonal Engineer · 2020–2023

Started working at 14 on my own initiative. Four consecutive summers at an institution of the National Academy of Sciences of Ukraine.

Reach me.

Open to AI Engineer and AI Product Engineer roles, remote. I can start as soon as there's an offer.

Reach me