Quicknode: Blockchain Data Access for Agents

• API key: Create a Quicknode account, get an endpoint URL with auth baked in. Full access to all products and settings.
• x402 (no account needed): Any wallet with USDC can authenticate and pay per request. Install

  @quicknode/x402

  and start querying immediately.

x402 Access (Recommended for Agents)

import { createQuicknodeX402Client } from "@quicknode/x402";

const client = await createQuicknodeX402Client({
  baseUrl: 'https://x402.quicknode.com',
  network: "eip155:84532",   // pay on Base Sepolia (testnet)
  evmPrivateKey: process.env.PRIVATE_KEY,
  preAuth: true,             // pre-authenticates via SIWX for faster payment flow
});

// Pay on Base, query any chain
const res = await client.fetch("https://x402.quicknode.com/ethereum-mainnet", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({ jsonrpc: "2.0", method: "eth_blockNumber", params: [], id: 1 }),
});

npm install @quicknode/x402

• Testnet: 100 credits for $0.01 USDC
• Mainnet: 1,000,000 credits for $10 USDC
• 1 credit per successful JSON-RPC response

API Key Access

https://{ENDPOINT_NAME}.{NETWORK}.quiknode.pro/{API_KEY}/

import { createPublicClient, http } from "viem";
import { base } from "viem/chains";

const client = createPublicClient({
  chain: base,
  transport: http(process.env.QUICKNODE_RPC_URL),
});

const block = await client.getBlockNumber();

Common Agent Operations

Check Native Balance (EVM)

const balance = await client.getBalance({ address: "0x..." });

{ "jsonrpc": "2.0", "method": "eth_getBalance", "params": ["0x...", "latest"], "id": 1 }

Check ERC-20 Token Balance (EVM)

eth_call

balanceOf(address)

0x70a08231

{
  "jsonrpc": "2.0",
  "method": "eth_call",
  "params": [{
    "to": "0xTOKEN_CONTRACT",
    "data": "0x70a08231000000000000000000000000WALLET_ADDRESS_NO_0x"
  }, "latest"],
  "id": 1
}

Get Gas Estimate (EVM)

{ "jsonrpc": "2.0", "method": "eth_gasPrice", "params": [], "id": 1 }

Check Transaction Status (EVM)

{ "jsonrpc": "2.0", "method": "eth_getTransactionReceipt", "params": ["0xTX_HASH"], "id": 1 }

Solana Balance

{ "jsonrpc": "2.0", "method": "getBalance", "params": ["WALLET_PUBKEY"], "id": 1 }

Solana Token Accounts

{
  "jsonrpc": "2.0",
  "method": "getTokenAccountsByOwner",
  "params": [
    "WALLET_PUBKEY",
    { "programId": "TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA" },
    { "encoding": "jsonParsed" }
  ],
  "id": 1
}

Quicknode Marketplace Add-ons

• Token API:

  qn_getWalletTokenBalance

  returns all ERC-20 balances for a wallet in one call. No need to query each token contract individually.
• NFT API:

  qn_fetchNFTs

  returns NFTs owned by an address with metadata.
• Solana Priority Fee API:

  qn_estimatePriorityFees

  returns recommended priority fees based on recent network activity. Useful for ensuring transactions land quickly.
• Solana DAS API: Query compressed NFTs, fungible tokens, and digital assets via methods like

  getAssetsByOwner

  and

  searchAssets

  .
• Metis - Solana Trading API: Jupiter-powered token swaps on Solana. Get quotes and execute swaps via

  quoteGet

  and

  swapPost

  endpoints. Docs: https://www.quicknode.com/docs/solana/metis-overview

Supported Networks

base-mainnet

ethereum-mainnet

polygon-mainnet

solana-mainnet

unichain-mainnet

https://x402.quicknode.com/{network-slug}

Error Handling

• 429 Too Many Requests: Back off and retry. Use exponential backoff.
• 402 Payment Required (x402): Credits depleted.

  @quicknode/x402

  handles this automatically by triggering a new USDC payment.
• JSON-RPC errors (e.g.,

  -32000

  ): Method-specific errors. Check params and retry.

Resources

• AI & Agents docs: https://www.quicknode.com/docs/build-with-ai
• Full RPC documentation (all chains): https://www.quicknode.com/docs/llms.txt
• x402 technical details: https://x402.quicknode.com/llms.txt
• Code examples (x402): https://github.com/quiknode-labs/qn-x402-examples
• Marketplace add-ons: https://marketplace.quicknode.com
• Full Quicknode skill with extended references: https://github.com/quiknode-labs/blockchain-skills/tree/main/skills/quicknode-skill