Crashout: Truly bet on anything

Inspiration

The idea for CrashOut came from seeing platforms like Kalshi, which let people bet on world events, but we wanted to take that idea and bring it closer to everyday life. Instead of politics or sports, we wanted to make it about your friends, your nights out, and your chaotic hangouts. Every group has that one night that turns unpredictable, so we thought, why not make it a game? CrashOut was built to make social moments fun, competitive, and meaningful by giving everyone the power to truly bet on anything.

What it does

CrashOut is a mobile-first social prediction app that lets you and your friends create private groups, pool money, and make bets on what you think will happen that night. From “who will text their ex” to “who will disappear before midnight,” anything goes. You assign confidence percentages to your top predictions, lock them in, and vote afterward to see who was right. Payouts depend on how confident and correct your predictions were, making every night a blend of chaos, strategy, and laughter.

It’s like a local version of Kalshi, but personal and built for your friend group. Whether it’s a party, date, or casual hangout, you can now bet on truly anything.

How we built it

CrashOut was built using Next.js 14, TypeScript, Tailwind CSS, and Zustand for client state management. We used Supabase for data persistence and authentication. The entire app was designed to be mobile-first, with smooth transitions and a clean, responsive interface.

We implemented multiple game modes to make each night unique:

• Classic Mode for the standard game flow.
• Roulette Mode, where users can spin to randomize their percentage allocations across predictions.
• Balanced Mode, which enforces fair play with min and max allocation limits.
• Chaos Mode, which adds extra predictions, quicker rounds, and unpredictable results.

We also added party management features, allowing hosts to cancel games and refund buy-ins, and letting non-hosts leave early if needed. Both actions are handled gracefully with confirmation dialogs, refund transactions, and updates to the wallet system.

The results flow was overhauled to make sure no data is ever lost. Results are recorded when parties settle, fetched from the backend if missing, and stored locally for instant access. We also built a share card generator that creates visually appealing summaries of each game, with two designs:

• A dark themed social share card with gradients, badges, and prediction highlights.
• A store receipt style card that looks like a thermal printer slip with itemized winnings.

AI assistance was used for ranking predictions and generating playful ideas for outcomes (ex. X will not make it to Keeps or Y will text his Ex), helping us create a fun and dynamic experience while keeping the flow lightweight.

Challenges we ran into

The biggest challenge was keeping everything consistent across multiple game modes while maintaining a clean architecture. We had to rethink how the Party interface stored game data so that each mode’s rules (like min/max limits or randomization) worked without breaking the core logic. Implementing refunds and cancel/leave flows also required careful wallet balance updates and syncs between the frontend store and backend API.

Another major challenge was ensuring that results were always retrievable even if users refreshed, left, or rejoined the app later. Fixing the results flow took multiple iterations to guarantee that no user’s game history or payouts would ever disappear. Building and testing the share card visualizations in limited time was also tricky, but the end result turned out both clean and fun.

Accomplishments that we're proud of

We’re proud of creating a fully working multiplayer experience that feels fast, social, and funny. CrashOut now supports multiple game modes, real-time interactions, cancel and leave features, reliable results storage, and two polished share card designs. The app feels like something you could actually use with friends during a night out, which is exactly what we wanted to achieve.

What we learned

We learned how to adapt the concept of prediction markets into something social, engaging, and accessible. We got hands-on experience building stateful multiplayer flows, managing wallets and payouts, and handling refund transactions in a way that feels seamless.

Most importantly, we learned how to balance creative chaos with good UX. The project taught us how to move fast while keeping a fun and reliable user experience at the core.

What's next for CrashOut: Truly bet on anything

Next, we want to take CrashOut beyond a hackathon prototype. Our upcoming goals include:

• Real-money support through safe and compliant payment APIs.
• Live party feeds with proof-based prediction validation (photos, GPS, or chat logs).
• AI-powered prediction suggestions based on group behavior and context.
• Expanded game modes with time-based challenges and automatic round timers.
• Global leaderboards and streaks to make the experience more competitive.
• Cross-platform mobile app using React Native for a true on-the-go experience.

We plan to launch closed beta testing for verified friend groups and then scale into public group modes. The vision is to make CrashOut the ultimate platform where you can truly bet on anything; your nights, your friends, and every unexpected moment that makes life exciting. We hope everyone can keep ti Go On with CrashOut!

Built With

• canva
• css
• next.js
• supabase
• tailwind
• typescript
• zustand