A full-stack, peer-to-peer coinflip betting game on Solana

A full-stack, peer-to-peer coinflip betting game on Solana. Players connect a wallet, create or join on-chain game rooms, and compete head-to-head for 2× the stake. The UI updates in real time over WebSockets, outcomes are resolved on-chain with Orao VRF, and the backend tracks rooms, chat, and match history in MongoDB.

I open-sourced coinflip-casino for developers in Solana / Anchor smart contract development. This post walks through what it does, how the pieces fit together, and how to run it locally.

Live demo / site: https://www.flip.is/

Why I built this

• Learn full-stack Web3 game architecture (wallet + program + backend + UI)


• Study provably fair randomness with on-chain VRF integration


• Fork and customize a peer-to-peer on-chain betting room model

Most tutorials stop at a smart contract or a UI mockup. I wanted a complete vertical slice — wallet flow, on-chain logic, backend state, and a responsive frontend — so you can study or fork a production-shaped codebase.

What it does

• 
  Create a room — Pick Head or Tail, set bet amount, choose SOL or SPL token.


• 
  Join a room — Browse open games in the live lobby and match against another player.


• 
  PvP coinflip — When two players are in the same room, the backend triggers on-chain resolution.


• 
  2× payout — The winner receives double the bet (fees apply on-chain).


• 
  Room expiration — Open rooms older than 5 minutes with no opponent are expired and refunded automatically.


• 
  Portfolio stats — Win count and total games per wallet.


• Wallet connect — players sign in with a Solana wallet


• Peer-to-peer rooms — create or join head-to-head matches

Architecture at a glance

• 
  Wallet layer — users connect a Web3 wallet to sign transactions


• 
  On-chain program — Anchor/Rust logic for escrow, rooms, and settlement


• 
  Randomness — verifiable flip outcomes via Orao VRF on Solana


• 
  Real-time layer — WebSocket events push room and flip state to the UI


• 
  Persistence — MongoDB stores rooms, chat, and historical match data


• 
  Application layer — TypeScript backend/frontend tying on-chain and off-chain flows
  

User Wallet  →  On-chain Program  →  VRF / Settlement

                    ↓

              Backend (API + WebSockets)  →  MongoDB / state

                    ↓

                 Frontend UI (real-time)

Adjust the diagram to match your repo layout if components differ.

Tech stack

• Solana


• Anchor


• TypeScript


• MongoDB


• WebSockets


• Orao VRF


• React

Quick start

git clone https://github.com/xxniiinxx/coinflip-casino.git

cd coinflip-casino

Setup steps:

1. Install dependencies (see README — typically npm install or yarn)


2. Copy .env.example to .env and fill in RPC, wallet, and API keys


3. Run local validator or point to devnet/mainnet as documented


4. Start the backend and frontend; connect wallet and create a test room

See the full README for environment variables, deploy scripts, and test commands: https://github.com/xxniiinxx/coinflip-casino

Video walkthrough

• 
  Coinflip Casino on Solana tutorial — How to set up and run coinflip-casino step by step


• 
  Coinflip Casino on Solana — Coinflip Casino on Solana — architecture and demo walkthrough

What to explore in the repo

• Program / contract entrypoints and account models


• API routes and WebSocket event handlers


• Frontend wallet adapter and game room components


• Tests, scripts, and deployment configs

Contributing

Issues and PRs are welcome. If this helped you learn something, a ⭐ on GitHub makes it easier for others to find.

Links

• 
  Video: https://www.youtube.com/watch?v=B0pLXF-sOuo
  


• 
  GitHub: https://github.com/xxniiinxx/coinflip-casino
  


• 
  Website: https://www.flip.is/
  

Disclaimer: Educational content only. Not financial advice. Gambling and trading involve risk; use responsibly and comply with local laws.

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