🎯 Smart Contracts 101
55 minutes to write your first trustless code on Bitcoin. Build and deploy an escrow smart contract on Citrea that holds funds until both parties confirm delivery — code is law, no middlemen.
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Code is Law on Bitcoin
Solidity contracts deployed to Citrea settle to Bitcoin. Once deployed, the code cannot be changed — perfect for Arcade marketplaces, tournaments, and escrows.
🚀 What You'll Build
A simple 2-party escrow contract on Citrea. Buyer deposits, seller confirms delivery, buyer releases or disputes — all on-chain and trustless. Deploy it, fund it, and use it for your first peer-to-peer Arcade trade.
📚 Quick Concepts
- Solidity Basics: contract, function, modifier, require, payable.
- Escrow: Smart contract that holds funds until conditions are met.
- Trustless Execution: Code runs exactly as written, no human can alter it after deployment.
- Deployment: Compile with Remix → deploy to Citrea testnet.
🔨 Build Steps
- Open Remix.ethereum.org, create new Solidity file.
- Paste the provided Escrow.sol template (with buyer/seller roles, deposit, release, refund).
- Compile, switch network to Citrea testnet, deploy.
- Fund the contract as buyer, simulate seller confirmation, release funds.
- View the contract on Citrea explorer — your first ₿app is live!
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Singularity-Aware Reality Check
When AI agents trade with each other in the Arcade, they will use smart contracts like yours — code is the only law they respect.
⚡ Lightning Network
The first major Layer 2—a network of payment channels enabling instant, near-free Bitcoin transactions.
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Instant Payments
Transactions confirm in milliseconds, not 10 minutes.
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Tiny Fees
Fractions of a cent per transaction—even for micropayments.
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Real-World Success: El Salvador
The Chivo wallet uses Lightning to enable everyday Bitcoin payments for 6+ million citizens.
🔶 What is Citrea?
Citrea is a Bitcoin Layer 2 that brings smart contracts to Bitcoin using zero-knowledge rollup technology. It's where Bitcoin Arcade Zone is built!
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You're Using Citrea Right Now!
Bitcoin Arcade Zone runs on Citrea Testnet (Chain ID 5115). When you claim prizes, they're paid in cBTC on Citrea!
Citrea's Key Features
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Smart Contracts
Ethereum-compatible (EVM) smart contracts powered by Bitcoin security. Build DeFi, NFTs, games—all on Bitcoin.
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ZK-Rollup
Validity proofs verified on Bitcoin—mathematically impossible to cheat. Inherit Bitcoin's security.
Built on Bitcoin's security, not a separate chain. BTC is the native asset.
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Fast & Cheap
Thousands of transactions per second with fees under $0.01. Ready for mass adoption.