Make Your First NOWNodes Request

After you create a NOWNodes account and generate an API key, you can send your first blockchain request. This guide shows how to choose an endpoint, authenticate the request, send it, and check the response.

Before you send a request

Make sure you have:

• an active NOWNodes API key;
• a network endpoint, for example Ethereum, Bitcoin, BNB Smart Chain, Solana, or Polygon;
• a request tool such as curl, Postman, Insomnia, or your application code.

For a quick test, Ethereum eth_blockNumber is a good first request because it does not require parameters and returns the latest block number.

Choose a network endpoint

Every supported network has its own endpoint. For example:

Choose the interface based on what your application needs:

• RPC / JSON-RPC for standard blockchain requests.
• WSS for real-time subscriptions and streams.
• Blockbook for explorer-style indexed data.
• gRPC for supported networks that expose gRPC services.
• Trace & Debug for low-level execution inspection on supported EVM networks.
• Archive mode when you need historical state beyond standard node retention.

Authenticate your request

Most NOWNodes HTTP RPC requests can be authenticated in one of two ways.

Option A: API key in the header

Use the api-key header when your backend or client library lets you configure request headers separately from the endpoint URL.

curl --request POST 'https://eth.nownodes.io' \
  --header 'Content-Type: application/json' \
  --header 'api-key: YOUR_API_KEY' \
  --data '{
    "jsonrpc": "2.0",
    "method": "eth_blockNumber",
    "params": [],
    "id": 1
  }'

Option B: API key in the URL path

Use the URL path format when a tool expects a single endpoint URL and does not make header configuration convenient.

curl --request POST 'https://eth.nownodes.io/YOUR_API_KEY' \
  --header 'Content-Type: application/json' \
  --data '{
    "jsonrpc": "2.0",
    "method": "eth_blockNumber",
    "params": [],
    "id": 1
  }'

Both options authorize the same request. For server-side applications, the api-key header is usually easier to keep separate from endpoint URLs.

Send your first request

Run one of the Ethereum examples above after replacing YOUR_API_KEY with your real key. The request asks Ethereum for the latest block number using the eth_blockNumber JSON-RPC method.

Check the response

A successful Ethereum eth_blockNumber response returns the latest block number in hexadecimal format:

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x123456"
}

If you receive an authentication error, check that:

• the API key is active;
• the key is copied without extra spaces;
• you are using the correct endpoint for the network;
• the key is passed either in the api-key header or in the URL path;
• your plan supports the endpoint or method you are trying to call.

If you need help choosing a plan, deploying a dedicated node, or connecting a network that is not listed, contact [email protected].