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Get Started in 5 Minutes

This guide will walk you through making your first paid crypto intelligence query on Arcana x402.
This quickstart assumes you already have MetaMask installed. If not, visit metamask.io first.

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Step 1: Add Base Sepolia Network

1

Open MetaMask

Click the MetaMask extension in your browser and ensure you’re logged in.
2

Add Network

Click the network dropdown at the top and select Add Network → Add a network manually.
3

Enter Network Details

Fill in the Base Sepolia testnet information:
  • Network Name: Base Sepolia
  • RPC URL: https://sepolia.base.org
  • Chain ID: 84532
  • Currency Symbol: ETH
  • Block Explorer: https://sepolia.basescan.org
Click Save when done.
The platform will automatically prompt you to switch to Base Sepolia when making payments.

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Step 2: Get Test ETH (Gas)

You’ll need Base Sepolia ETH to pay for transaction gas fees.
1

Visit Base Sepolia Faucet

Navigate to a Base Sepolia faucet:
2

Request Test ETH

Enter your wallet address and complete any required verification (captcha, social login, etc.).You should receive 0.05-0.1 ETH within a few minutes.
3

Verify Balance

Check your MetaMask to confirm the ETH arrived. Switch to Base Sepolia network to see the balance.

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Step 3: Get Test USDC

Queries cost $0.03 USDC each. You’ll need Base Sepolia test USDC.
1

Get the USDC Contract Address

Base Sepolia USDC address:
0x036CbD53842c5426634e7929541eC2318f3dCF7e
2

Visit a Multi-Token Faucet

Some options:
3

Import USDC to MetaMask

In MetaMask:
  1. Go to Assets tab
  2. Scroll down and click Import tokens
  3. Paste the USDC contract address: 0x036CbD53842c5426634e7929541eC2318f3dCF7e
  4. Click Add Custom Token
You should now see your USDC balance.
Make sure you’re on Base Sepolia network when importing the USDC token. The contract address is different on each network.

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Step 4: Connect to Arcana x402

1

Visit the Platform

Open the Arcana x402 web interface at your deployment URL (e.g., http://localhost:5173 for local development).
2

Connect Wallet

Click the Connect Wallet button in the top right corner.Select MetaMask and approve the connection request.
3

Sign Verification Message

You’ll be prompted to sign a message to verify wallet ownership. This doesn’t cost gas.Click Sign in the MetaMask popup.
4

Verify Connection

After signing, you should see:
  • Your wallet address in the header
  • Your ETH and USDC balances
  • The chat input becomes enabled
The signature verification is cached for 24 hours. You won’t need to sign again on every visit.

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Step 5: Make Your First Query

1

Type Your Question

In the chat input at the bottom, type a crypto question. Examples:
  • “What’s the current price of Bitcoin?”
  • “Show me top yield farming opportunities”
  • “What’s the floor price for Bored Ape Yacht Club?”
  • “Give me the latest crypto news”
2

Send Payment

Click Send or press Enter.MetaMask will open asking you to approve a USDC transfer of $0.03:
  • Amount: 0.03 USDC
  • To: Provider Agent Address
  • Network: Base Sepolia
Review and click Confirm.
3

Wait for Processing

After the transaction confirms:
  1. You’ll see “Waiting for payment confirmation…”
  2. The backend verifies your transaction on-chain
  3. Gemini AI decides which agents to call
  4. Agent responses are aggregated
  5. Your answer appears in the chat
This usually takes 5-15 seconds.
4

Review Response

The AI response will show:
  • The answer to your question
  • Which agents were used (e.g., “Price Oracle”, “News Scout”)
  • Transaction hash for your payment

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Example Query Flow

Here’s what happens behind the scenes: 
// 1. User approves USDC transfer
const txHash = await ethereum.request({
  method: 'eth_sendTransaction',
  params: [{
    from: userAddress,
    to: USDC_ADDRESS, // 0x036CbD...
    data: encodeFunctionData({
      functionName: 'transfer',
      args: [PROVIDER_ADDRESS, parseUnits('0.03', 6)]
    })
  }]
});

// 2. Send query with transaction hash
const response = await fetch('/query', {
  method: 'POST',
  body: JSON.stringify({
    query: 'What is the price of Bitcoin?',
    txHash,
    userAddress
  })
});

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Troubleshooting

This means you don’t have enough USDC or ETH:
  • Check you have at least 0.03 USDC for the query
  • Check you have at least 0.001 ETH for gas fees
  • Make sure you’re on Base Sepolia network
  • Revisit Step 2 and Step 3 to get more test tokens
If your payment was confirmed but you didn’t get a response:
  • Check the backend is running (GET /health should return 200)
  • Verify VITE_API_URL in frontend .env matches backend URL
  • Check browser console for errors
  • Your $0.03 payment was recorded - contact support with your transaction hash
The frontend checks if the backend is reachable before charging you:
  • Confirm backend is running: http://localhost:3001/health
  • Check VITE_API_URL environment variable
  • Verify no firewall is blocking the connection
  • If using local dev: make sure both frontend and backend are started
If the signature request is rejected:
  • Try disconnecting and reconnecting your wallet
  • Clear browser cache and localStorage
  • Make sure you’re using a supported browser (Chrome, Firefox, Brave)
  • Check MetaMask is unlocked and on the correct network
If your transaction doesn’t confirm:
  • Base Sepolia testnet can be slow - wait 1-2 minutes
  • Check Base Sepolia Explorer with your tx hash
  • Try increasing gas limit in MetaMask settings
  • Ensure you have enough ETH for gas (at least 0.001 ETH)

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Next Steps

Now that you’ve made your first query:

Explore Agents

Learn about all 7 specialized agents and their capabilities

Dashboard

View your query history, spending, and agent usage stats

API Reference

Integrate Arcana x402 into your own applications

Policy Controls

Set spend limits, freeze agents, and configure allowlists
Want to run your own instance? Check out the Local Development Guide for developers.

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