AvalanchePredict

A privacy-preserving prediction market platform on Avalanche, powered by Fhenix Fully Homomorphic Encryption (FHE). Built entirely through vibecoding with Matterhorn.

Live Demo: https://frontend-lyart-seven-39.vercel.app

GitHub: https://github.com/matterhornso/Avalanchebuildgames

What It Does

AvalanchePredict lets users browse prediction markets on real-world outcomes — crypto prices, DeFi milestones, regulatory events, and more — and place Yes/No bets using native AVAX. When a market resolves, winners claim payouts proportional to their stake in the winning pool.

What makes it different: bet amounts are encrypted on-chain using Fhenix CoFHE. No one — not other users, not the contract operator, not block explorers — can see how much anyone bet. Only participant counts are public. This prevents front-running, copycat betting, and social pressure that plague transparent prediction markets.

The app ships with 25 sample markets across 5 categories so you can explore the full experience without deploying anything.

How It Was Built — Vibecoding with Matterhorn

This entire project — smart contracts, deploy scripts, tests, frontend, and deployment — was vibecoded from scratch using Matterhorn, an AI-powered IDE for blockchain developers.

Here's what that looked like in practice:

1. Smart contract generation — Started with a single prompt: "Create a simple prediction market platform on Avalanche with 10 sample markets." Matterhorn scaffolded a Foundry project, wrote the Solidity contract with market creation, binary betting, resolver-based settlement, and proportional payout math, then generated a deploy script and 7 passing tests — all in one shot.

2. Frontend in one pass — Asked for "a sleek front-end" and Matterhorn built a full React + Vite + TypeScript app with wallet connection, market browsing, category filtering, search, bet placement, payout claiming, and a dark glassmorphism Avalanche-themed design. Later upgraded to 25 markets across 5 categories with staggered animations and responsive grid layout.

3. FHE privacy integration — Adding Fhenix CoFHE encryption was a single prompt. Matterhorn wrote a new PrivatePredictionMarket.sol using euint64 encrypted values, configured Foundry remappings for the CoFHE library, and updated the frontend with privacy indicators, encryption animations, and participant-count-only displays.

4. Deployment — Vercel deployment was handled through Matterhorn's built-in terminal integration. Local testing used Matterhorn's Anvil integration with automatic contract deployment.

No boilerplate was written by hand. No copy-pasting from tutorials. The entire development cycle — from empty folder to deployed app — happened through natural language conversation with Matterhorn.

Architecture

├── src/
│   ├── PredictionMarket.sol          # Standard prediction market (Avalanche-ready)
│   └── PrivatePredictionMarket.sol   # FHE-encrypted bets via Fhenix CoFHE
├── script/
│   └── Deploy.s.sol                  # Foundry deploy script (10 on-chain markets)
├── test/
│   └── PredictionMarket.t.sol        # 7 Foundry tests
└── frontend/                         # React + Vite + TypeScript
    └── src/
        ├── App.tsx                   # Main app with 25 demo markets
        ├── contract.ts               # ABI and contract config
        └── index.css                 # Glassmorphism theme

Smart Contracts

PredictionMarket.sol — The core contract deployed on Avalanche. Supports:

• Market creation with custom questions, options, deadlines, and resolvers
• Binary Yes/No betting with native AVAX
• Resolver-based market settlement
• Proportional payout distribution to winners
• Full revert protection (expired markets, double claims, unresolved markets)

PrivatePredictionMarket.sol — The privacy-enhanced version using Fhenix CoFHE:

• Bet amounts stored as euint64 encrypted values
• FHE.add() for encrypted pool accumulation without revealing individual bets
• FHE.select() for constant-time payout branching (no timing side channels)
• FHE.allowThis() / FHE.allowSender() for encrypted state access control
• Only participant counts are exposed publicly

Frontend

• 25 sample markets across 5 categories: Crypto, DeFi, Regulation, Avalanche, Tech
• Category tab filtering and search
• Glassmorphism card design with ambient glow effects and staggered fade-in animations
• Click-to-expand bet panels with Yes/No buttons
• FHE privacy badges, encryption indicators, and participant-count-only pool displays
• Wallet connection with account display and network detection
• Demo mode that works without any contract deployment
• Fully responsive layout

Privacy Design (Fhenix FHE)

Traditional prediction markets expose all bet amounts on-chain. This creates problems:

• Front-running — MEV bots can see large bets and trade ahead
• Copycat betting — Users mimic whale positions instead of forming independent views
• Social pressure — Public bets discourage contrarian positions

AvalanchePredict solves this with Fhenix CoFHE (Cooperative Fully Homomorphic Encryption). Individual bet amounts are encrypted before being stored on-chain. The contract can still compute aggregate pool totals and payouts using FHE arithmetic — without ever decrypting individual bets.

Network note: CoFHE currently supports Ethereum Sepolia, Arbitrum Sepolia, and Base Sepolia. The standard PredictionMarket.sol works on Avalanche today. When Fhenix adds Avalanche support, the private contract can be deployed directly.

Quick Start

Build & Test

forge build
forge test

Run Locally

# Terminal 1: Start local Avalanche node
anvil

# Terminal 2: Deploy contract with sample markets
forge script script/Deploy.s.sol:Deploy --rpc-url http://127.0.0.1:8545 --broadcast

# Terminal 3: Start frontend dev server
cd frontend && npm install && npm run dev

Open the URL printed by Vite (e.g. http://localhost:5173). Connect a wallet to localhost:8545 (chain ID 31337).

The frontend also runs in demo mode with all 25 sample markets if no contract is deployed — just start the frontend and go.

FHE Testing (Hardhat)

npm install
npx hardhat test

Tech Stack

• Contracts: Solidity 0.8.25, Foundry, Hardhat
• Privacy: Fhenix CoFHE (@fhenixprotocol/cofhe-contracts)
• Frontend: React 18, Vite, TypeScript, ethers.js v6
• Chain: Avalanche C-Chain
• Deployment: Vercel (frontend), Foundry scripts (contracts)
• Development: Vibecoded with Matterhorn

License

MIT