Derby Party App

About this app

Throw a Derby party that runs like clockwork. Derby Party is the app for hosting a pari-mutuel betting pool at any horse race — Kentucky Derby, Preakness, Belmont, Breeders' Cup, Royal Ascot, Melbourne Cup, or any race you set up yourself. THE APP DOES THE MATH SO YOU CAN ENJOY THE PARTY The wizard walks you through six steps: 1. Create or import a race 2. Add the field of horses with their odds 3. Add your party guests 4. Place every bet — Win, Place, Show, Across the Board, Exacta, Trifecta 5. Enter the finishing order 6. Calculate exact pari-mutuel payouts — with the math shown LIVE TOTE BOARD FOR YOUR GUESTS Press ⇧⌘T to open a betting board on a second monitor. Guests see live pool sizes, the crowd favorite, projected payouts per horse, a countdown to post time, and big "BETS CLOSED" indicator when wagering ends. Drag it onto any external display. BUILT FOR THE BUSY HOST • Fast keyboard-first bet entry (lock the bettor, ⌘↩ to save and start the next one) • Print blank bet slips (2 per page) so guests can write their wagers on paper while you transcribe • Print a master bet ledger before post time — guests initial each bet, settling any "I bet on Justify, not Always Dreaming" disputes • Print a bet types reference handout for guests new to horse racing • Lock bets at post time (manually or automatically) to keep the record honest • "Surprise me!" picks a random horse for guests who can't decide DATA SAFETY Every change auto-snapshots to a sandbox-safe location. If anything goes wrong — accidental delete, app crash, drive failure — File → Restore from Backup recovers your party from minutes ago. Press ⌘Z to undo within the session. Save errors are surfaced immediately, never silently swallowed. EMAIL EVERY WINNER After Calculate Payouts, click Email Winners. Each winning guest gets a personalized email with their bet, the math, the result, and what they won. Brings the party energy days later. SIDE CONTESTS Best Hat, Best Mint Julep, Best Outfit — pick a winner and print a fancy landscape certificate to hand them. RACE DATA INCLUDED The app comes free; race data for major events is sold per-event-year ($4.99 each) as in-app purchase. One purchase unlocks every race on that day's card. We curate the data for accuracy and update post positions as the official entries are published. PARI-MUTUEL MATH, VERIFIED Payouts are calculated using the same battle-tested algorithm as the 13-year-old DerbyParty iPad app. Every winning bet gets exactly its fair share of the pool, with optional house cut for fundraisers. The calculation trace is shown in full so you can prove every dollar. PRIVACY-FIRST All data — bettors, bets, results — stays on your Computer in a sandboxed local database. We collect nothing, transmit nothing, and have no servers that hold your party data. REQUIREMENTS • macOS 14.0 or later • Optional second display for the Tote Board • Printer (optional, for paper records) Created by Larson Development. Support at derbyparty@larsdev.com.

Momentum comes from crawler snapshots for the tracked storefront. “Viral growth signal” means unusually fast recent rating gains; it is an indicator, not download data.

1. First observed Aug 7, 2026 · 11:18 PM $49.99