chain_subscribeNewHeads

Retrieves the best header via subscription.

For clients that require regular updates of the most important or "best" block headers as they are added to the blockchain, the chain_subscribeNewHeads RPC technique is invaluable. With no need for repetitive manual queries, this subscription-based method offers timely header data—essential for applications needing the most recent blockchain information.

Example Request and Result for chain_subscribeNewHeads method

In this section, we provide an illustrative example of a request made to retrieve details contents using the chain_subscribeNewHeads method. Additionally, we present the resulting response containing information about getting the best header using WS subscription.

Parameters

Fields	Type	Description
subscription	string	Allows the client to manage the subscription

info

The example in this section uses a non-existing project id.

Make sure you replace it with your Vara Mainnet endpoint when issuing the API calls.

Don't have a project id? Here's a straightforward guide on how to obtain one!

Retrieves the best header via subscription

POST wss://vara-mainnet.blastapi.io/<project-id>

Request Body

Name	Type	Description
subscription	string	[]

200: OK Expand for a detailed response example

{
  "jsonrpc": "2.0",
  "method": "chain_newHead",
  "params": {
    "subscription": "3pEL6Gp7F7yQluGJ",
    "result": {
      "parentHash": "0x45498c7ebdc8a3bc4b326c0660a4515ce795cc2a0c12fc459c6f700c40d6edd1",
      "number": "0x9a2946",
      "stateRoot": "0x94078bf8f35254ffba013669752428c941c24d457bd16ff97a444a8a7af61191",
      "extrinsicsRoot": "0x949ca67ba029850ec54f3b768bd88f54082050381ea5b167ca14aec7749aa610",
      "digest": {
        "logs": [
          "0x064241424534021f0000009c04f92100000000",
          "0x054241424501011cdcfea6fc688511504d78f1bb32c3a2178fdaeaee7eb11234707c63d307ae7220055a65930f1aa5c26b1d9122df9720417a2c10c9fc309cb2ab8fb95836c58b"
        ]
      }
    }
  }
}

Curl Request example

wscat -c 'wss://vara-mainnet.blastapi.io/<project-id>'
# wait for connection
messasge:
{
    "id": 1,
    "jsonrpc": "2.0",
    "method": "chain_subscribeNewHeads",
    "params": []
}