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This subscription is considered unstable and is only available if the validator was started with the --rpc-pubsub-enable-block-subscription flag. The format of this subscription may change in the future.
This is an unstable RPC method that Helius does not support. This documentation is provided for reference only.

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Endpoints

Websockets are available on mainnet and devnet with the following URLs:
  • Mainnet wss://mainnet.helius-rpc.com/?api-key=<API_KEY>
  • Devnet wss://devnet.helius-rpc.com/?api-key=<API_KEY>
Websockets have a 10-minute inactivity timer; implementing health checks and sending pings every minute is heavily recommended to keep the websocket connection alive.

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Authorizations

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api-key
string
required
Your Helius API key. You can get one for free in the dashboard.

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Body

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params
array
required

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Response

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result
integer
Subscription id (needed to unsubscribe)

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Notification Format

The notification will be an object with the following fields:
  • slot: <u64> - The corresponding slot.
  • err: <object|null> - Error if something went wrong publishing the notification otherwise null.
  • block: <object|null> - A block object as seen in the getBlock RPC HTTP method.
{
  "jsonrpc": "2.0",
  "id": "1",
  "method": "blockSubscribe",
  "params": [
    {
      "mentionsAccountOrProgram": "LieKvPRE8XeX3Y2xVNHjKlpAScD12lYySBVQ4HqoJ5op"
    },
    {
      "commitment": "confirmed",
      "encoding": "base64",
      "showRewards": true,
      "transactionDetails": "full"
    }
  ]
}

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