OP Face — Bitcoin NFT on OP_NET

A limited-edition NFT minting dApp running entirely on Bitcoin via OP_NET. Only 100 faces will ever exist.

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Overview

Property	Value
Name	OP Face
Symbol	OPFACE
Max Supply	100
Mint Price	0.005 tBTC (500,000 sat)
Treasury	bcrt1pzcu0e6e04uc5l43fvrr2czh2fxh5my8c08ggnywghw3hchznqdcsr9x2s9
Network	OP_NET Testnet (regtest / signet)
Contract	AssemblyScript → WASM, deployed on OP_NET

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Project Structure

op-face/
├── contract/                  # AssemblyScript smart contract
│   ├── src/
│   │   ├── contracts/
│   │   │   └── OPFace.ts      # Main NFT contract
│   │   └── index.ts           # WASM entry point
│   ├── abis/
│   │   └── OPFace.json        # ABI definition
│   ├── scripts/
│   │   └── deploy.ts          # Deployment script
│   ├── build/                 # Compiled WASM output (generated)
│   ├── asconfig.json          # AssemblyScript config
│   ├── tsconfig.json
│   └── package.json
│
├── frontend/                  # Next.js 14 dApp
│   ├── src/
│   │   ├── app/
│   │   │   ├── layout.tsx
│   │   │   ├── page.tsx       # Mint page (home)
│   │   │   └── token/[id]/
│   │   │       └── page.tsx   # Token detail page
│   │   ├── components/
│   │   │   ├── WalletConnect.tsx
│   │   │   ├── MintForm.tsx
│   │   │   ├── Gallery.tsx
│   │   │   └── TokenCard.tsx
│   │   ├── lib/
│   │   │   ├── contract.ts    # OP_NET contract calls
│   │   │   ├── wallet.ts      # Wallet utilities
│   │   │   └── ipfs.ts        # IPFS upload helpers
│   │   └── types/
│   │       └── index.ts
│   ├── .env.example
│   ├── next.config.js
│   ├── tailwind.config.js
│   └── package.json
│
└── README.md

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Prerequisites

• Node.js ≥ 18
• OP_WALLET browser extension — https://opnet.org
• @opnet/cli — npm i -g @opnet/cli
• AssemblyScript — npm i -g assemblyscript
• Testnet tBTC from the OP_NET faucet

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1 — Build the Contract

cd contract
npm install
npm run build
# → build/OPFace.wasm

For an optimised (smaller) binary:

npm run build:optimized

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2 — Deploy to Testnet

cd contract

# Set your deployer private key (WIF format)
export DEPLOYER_WIF="cYourPrivateKeyHere..."

# Deploy to regtest
npx ts-node scripts/deploy.ts --network regtest

# Deploy to signet/testnet
npx ts-node scripts/deploy.ts --network testnet

The script prints the contract address on success. Copy it for the next step.

Alternatively, use the CLI directly:

opnet-deploy \
  --network regtest \
  --rpc https://regtest.opnet.org \
  --contract build/OPFace.wasm \
  --wif $DEPLOYER_WIF

---

3 — Configure the Frontend

cd frontend
cp .env.example .env.local

Edit .env.local:

NEXT_PUBLIC_CONTRACT_ADDRESS=<your-contract-address-from-step-2>
NEXT_PUBLIC_OPNET_RPC=https://regtest.opnet.org

# Optional: Pinata IPFS (recommended for production)
NEXT_PUBLIC_PINATA_API_KEY=
NEXT_PUBLIC_PINATA_API_SECRET=

---

4 — Run the Frontend

cd frontend
npm install
npm run dev
# → http://localhost:3000

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Contract API

Write Methods

Method	Parameters	Description
mint(tokenURI)	string	Mint NFT. Requires 0.005 tBTC payment.

Read Methods

Method	Returns	Description
totalSupply()	uint256	Current number of minted tokens
maxSupply()	uint256	Always 100
mintPrice()	uint256	Satoshi price (500,000)
name()	string	"OP Face"
symbol()	string	"OPFACE"
tokenURI(id)	string	IPFS metadata URI
ownerOf(id)	string	Current owner address
minterOf(id)	string	Original minter address
mintedAt(id)	uint256	Bitcoin block number of mint
tokenInfo(id)	multi	owner, minter, block, URI in one call

Events

Event	Fields
Transfer	from (string), to (string), tokenId (uint256)

---

Mint Flow

User selects image (PNG/JPG/GIF/WEBP ≤ 5MB)
        │
        ▼
Image uploaded to IPFS  →  ipfs://Qm{imageCID}
        │
        ▼
Metadata JSON built & uploaded to IPFS  →  ipfs://Qm{metaCID}
        │
        ▼
OP_NET SDK builds PSBT:
  • Input:  user UTXO (covers 500,000 sat + fee)
  • Output: calldata → mint(metaURI)
  • Value:  500,000 sat sent to contract
        │
        ▼
OP_WALLET signs PSBT
        │
        ▼
Transaction broadcast to Bitcoin
        │
        ▼
OP_NET executes contract:
  1. Validates supply < 100
  2. Validates value ≥ 500,000 sat
  3. Transfers 500,000 sat to treasury
  4. Stores token: owner, minter, timestamp, URI
  5. Emits Transfer event
  6. Returns tokenId
        │
        ▼
Frontend shows success + token detail page

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Treasury

All mint proceeds (0.005 tBTC per mint, up to 0.5 tBTC total) are sent automatically to:

bcrt1pzcu0e6e04uc5l43fvrr2czh2fxh5my8c08ggnywghw3hchznqdcsr9x2s9

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Tech Stack

Layer	Technology
Contract	AssemblyScript → WASM, OP_NET runtime
Chain	Bitcoin (via OP_NET smart contract layer)
Storage	IPFS (Pinata / NFT.Storage)
Frontend	Next.js 14, TypeScript, Tailwind CSS
SDK	@btc-vision/sdk, @btc-vision/btc-runtime
Wallet	OP_WALLET browser extension

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Development

# Lint
cd frontend && npm run lint

# Type check
cd frontend && npm run type-check

# Build for production
cd frontend && npm run build

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Testnet Resources

• OP_NET Testnet: https://regtest.opnet.org
• Explorer: https://explorer.opnet.org
• Faucet: https://faucet.opnet.org
• Wallet: https://opnet.org
• Docs: https://docs.opnet.org

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License

MIT