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Get started with CDP Node in minutes. This guide shows you how to get your RPC endpoint and make your first blockchain request—both in the browser playground and programmatically in your code.

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Prerequisites

That’s it! No complex setup, no infrastructure to manage.

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1. Try it in the playground

CDP Node provides free RPC endpoints for Base. With Node, you can:
  • Read blockchain state (blocks, transactions, balances, smart contract data)
  • Send transactions to the network
  • Monitor events and subscribe to logs
  • Call smart contracts on Base
Let's make your first blockchain call using the Node Playground in CDP Portal.
1

Open Node Playground

Navigate to Node in Portal.
2

Run the RPC call

The playground has a prefilled eth_blockNumber call. Click Run to get the current block number on Base. See results in milliseconds! ⚡
Node Playground RPC call results showing current block number

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2. Get your RPC endpoint

To use Node in your application, you need an RPC endpoint URL. This is the web address where you send blockchain requests—think of it like an API endpoint, but specifically for blockchain operations.
1

Navigate to Node

Go to the Node page in CDP Portal.
2

Select your network

Choose your target network from the dropdown:
  • Base Mainnet - For production applications
  • Base Sepolia - For development and testing
Network selection dropdown in Node configuration
3

Copy your endpoint URL

Copy the displayed RPC endpoint URL. It will look like:
https://api.developer.coinbase.com/rpc/v1/base/YOUR_CLIENT_API_KEY
The Client API key is automatically included in the URL for authentication.
About Client API KeysYour RPC endpoint URL includes a Client API key, which is designed for client-side use and is safe to include in frontend code. For more details, see CDP API Keys.

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3. Make your first request

Now let’s make your first blockchain request programmatically. We’ll query the current block number on Base.
  • cURL
  • JavaScript (fetch)
  • Python
  • Node.js
curl https://api.developer.coinbase.com/rpc/v1/base/YOUR_CLIENT_API_KEY \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "eth_blockNumber"
  }'
Response:
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x12a4b2c"
}
Using Ethereum libraries? Node works with any Ethereum-compatible library like ethers.js, viem, web3.js, or web3.py. Just use your RPC endpoint URL as the provider.
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