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Parameters

None. This method does not accept any parameters.

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Response

  • result - An integer subscription id (needed to unsubscribe)
  • subscription - An object containing detailed slot information:
    • slot - The current slot height
    • timestamp - The current estimated production time (as Unix timestamp) of the slot
    • type - The type of slot update:
      • "firstShredReceived" - The first shred of the slot was received
      • "completed" - The slot was completed
      • "createdBank" - The bank for the slot was created
      • "frozen" - The bank for the slot was frozen
      • "dead" - The bank for the slot was marked as dead
      • "optimisticConfirmation" - The slot was optimistically confirmed
      • "root" - The slot was rooted

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slotsUpdatesSubscribe code examples

This example subscribes to detailed slot updates.
Note that subscriptions require a WebSocket connection and WebSocket cat for you to use this method in the console.Install WebSocket cat with:npm install -g wscat
$ wscat -c YOUR_CHAINSTACK_WEBSOCKET_ENDPOINT
# Wait for the connection to be established

Connected (press CTRL+C to quit)

> {"jsonrpc":"2.0","id":1,"method":"slotsUpdatesSubscribe"}

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Use case

The slotsUpdatesSubscribe method is valuable for applications that need detailed monitoring of the Solana blockchain’s slot processing. Common use cases include:
  • Performance monitoring: Track detailed slot processing times and states
  • Debugging: Monitor slot processing stages for troubleshooting
  • Chain health monitoring: Track slot completion and confirmation rates
  • Analytics: Gather detailed metrics about blockchain performance
  • Advanced timing: Coordinate operations based on specific slot states
By subscribing to detailed slot updates, applications can gain deeper insights into the blockchain’s operation and implement more sophisticated timing and monitoring systems.
Last modified on October 19, 2025