Lucky Spin — Provably Fair Wheel Game on QTUM

A complete, open-source spin wheel dApp running on QTUM testnet. 1 QTUM per spin, 8 prize segments, on-chain settlement via commit-reveal.

QTUM Testnet MetaMask Snap Provably Fair 3.75% House Edge

What Is Lucky Spin?

Lucky Spin is a provably fair wheel-of-fortune game running on the QTUM blockchain testnet. Players connect their wallet through MetaMask with the qtum-wallet extension, pay 1 QTUM to spin a wheel with 8 prize segments, and receive automatic on-chain payouts.

The game uses a commit-reveal scheme to ensure that neither the house nor the player can predict or manipulate the outcome. The result is computed on-chain from keccak256(houseSeed + playerSeed + spinId) % 8, making every spin independently verifiable.

Try It Live

Play Lucky Spin right now at dice.ziesto.ca/spin. You'll need MetaMask and some testnet QTUM.

How It Works

Every spin follows this provably fair flow:

House Commits

The backend generates a secret house seed, stores it, and sends only the keccak256 hash to the frontend.

Player Commits

The frontend generates a random player seed, hashes it, and calls placeSpin() on the smart contract with both hashes plus 1 QTUM.

Both Reveal

After on-chain confirmation, the player sends their seed to the backend, which then calls revealAndResolve() with both seeds.

On-Chain Settlement

The contract computes keccak256(houseSeed + playerSeed + spinId) % 8 to determine the winning segment and automatically sends the prize.

Prize Structure

The wheel has 8 equal segments. Each spin costs exactly 1 QTUM:

Segment	Color	Payout	Net Result	Count	Chance
0, 4	Red	0.4 QTUM	-0.6 QTUM	2	25%
1, 5	Orange	0.7 QTUM	-0.3 QTUM	2	25%
2, 6	Green	1.1 QTUM	+0.1 QTUM	2	25%
3	Blue	1.3 QTUM	+0.3 QTUM	1	12.5%
7	Gold	2.0 QTUM	+1.0 QTUM	1	12.5%

House Edge

The expected value per spin is 0.9625 QTUM, calculated as:

EV = (2/8 × 0.4) + (2/8 × 0.7) + (2/8 × 1.1) + (1/8 × 1.3) + (1/8 × 2.0)
   = 0.1 + 0.175 + 0.275 + 0.1625 + 0.25
   = 0.9625 QTUM

// House edge = (1 - 0.9625) / 1 = 3.75%

Technology Stack

SpinGame.sol

Solidity smart contract handling spin placement, seed verification, segment calculation, and automatic payouts.

React + Three.js Frontend

3D spin wheel built with Three.js, bloom post-processing, particle effects, and MetaMask Snap integration.

Node.js Backend

Express server handling house seed generation, blockchain event monitoring, and reveal coordination.

MetaMask + qtum-wallet

Wallet connection and transaction signing via MetaMask's Snap framework for QTUM support.

Explore the Guides

Architecture

System overview, data flow diagrams, and how all components interact.

Snap Integration

Complete guide to qtum-wallet-connector: wallet connection, transactions, and address conversion.

Smart Contract

Full SpinGame.sol source with line-by-line explanation of every function.

API Reference

All backend endpoints with request/response examples.

Contract Address (Testnet)

Contract	Address
SpinGame	`33531da3d5d75c0dc1cd7e852c07c364d6072c8e`

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