Zerlin - STX Gas Calculator

Real-time fee estimation for Stacks blockchain

Why Zerlin?

Stacks users need to hold STX for transaction fees, but understanding how much STX to keep is non-obvious. Zerlin removes

Quick Start

Backend (with Swagger)

cd backend
pnpm install
pnpm start:dev

Swagger UI: http://localhost:3000/api

Contracts

cd contract
pnpm test  # Run tests
clarinet deployments generate --devnet  # Generate deployment plan

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API Endpoints

POST /api/estimate

Estimate transaction fee

Request:

{
  "type": "transfer",
  "payload": {
    "amount": 1000000,
    "recipient": "SP2X0TZ59D5SZ8ACQ..."
  }
}

Response:

{
  "transactionType": "transfer",
  "estimatedFee": {
    "stx": "0.000180",
    "microStx": 180,
    "usd": "0.00",
    "btc": 0
  },
  "breakdown": {
    "baseFee": 180,
    "executionCost": 0,
    "dataSize": 180
  },
  "networkStatus": {
    "congestion": "low",
    "averageFee": 1,
    "recommendedBuffer": 360
  }
}

GET /api/network

Get current network status

GET /api/history

Get recent fee estimates (last 50)

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Testing

Contract Tests

cd contract
pnpm test

Results: 88 passing tests ✅

Backend Tests

cd backend
pnpm test

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Deployment

Devnet

cd contract
clarinet deployments generate --devnet
clarinet deployments apply -p deployments/default.devnet-plan.yaml

Testnet

clarinet deployments generate --testnet
clarinet deployments apply -p deployments/default.testnet-plan.yaml

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Next Steps

Post-MVP Features

• Add back batch operations
• Implement WebSocket for real-time updates
• Build Next.js frontend
• Integrate wallet connections
• Add price feed for USD/BTC conversion

Documentation

• API integration guide
• Contract deployment guide
• Frontend integration examples

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Support

• Discord
• Twitter
• Email: [email protected]

Acknowledgments

Built with support from the Stacks Foundation and the Stacks community.