Quickstart: Blockchain RPC

Required roles

To get the permissions that you need to view API keys, ask your administrator to grant you the API Key Viewer ( roles/serviceusage.apiKeysViewer ) IAM role on your project. For more information about granting roles, see Manage access to projects, folders, and organizations .

You might also be able to get the required permissions through custom roles or other predefined roles .

Using the RPC endpoint

1. In the Google Cloud console, go to the Blockchain RPC page.

   Go Blockchain RPC

2. From the console, copy the JSON-RPC endpoint that matches the network and location combination you need.

   

3. Now you can begin making requests. A full list of all the RPC methods available are listed in the RPC API reference documentation. Our example request calls the eth_blockNumber method.

 curl  
-X  
POST  
-H  
 "Content-Type: application/json" 
  
-d  
 '{ 
 "jsonrpc": "2.0", 
 "id": 1, 
 "method": 
 "eth_blockNumber", 
 "params": []}' 
  
 \ 
 JSON_RPC_ENDPOINT 
 

Where:

• JSON_RPC_ENDPOINT is an endpoint you copied from the console. This endpoint includes a default API key that has been automatically created. You can manage all of your keys on the Credentials page.

After executing this curl request, you should see a response like:

  { 
 "jsonrpc" 
: "2.0" 
, "id" 
:1, "result" 
: "0x13acb8d" 
 } 
 

Using WebSocket subscriptions

WebSocket support is also enabled for Blockchain RPC endpoints. This example uses the wscat open source project.

1. In the Google Cloud console, go to the Blockchain RPC page.

   Go Blockchain RPC

2. From the console, copy the WebSocket endpoint that matches the network and location combination you need.

   

3. Now you can begin making requests.

 wscat  
-c  
 WS_ENDPOINT 
 

Where:

• WS_ENDPOINT is a WebSocket endpoint from the console.

Subscribe to new block headers:

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

You'll start receiving messages for each new block header.