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The Geyser plugin interface provides a way to build custom plugins that receive real-time notifications about accounts, transactions, blocks, and slots as they are processed by the Agave validator.

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Overview

Geyser plugins enable you to:
  • Stream account updates in real-time
  • Capture transaction execution details
  • Monitor block production
  • Track slot progression
  • Build custom indexers and data pipelines
Plugins are dynamically loaded libraries that implement the GeyserPlugin trait and receive callbacks from the validator runtime.

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Plugin Interface

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Account Updates

Plugins receive notifications when accounts are modified: 
pub struct ReplicaAccountInfoV3<'a> {
    /// The Pubkey for the account
    pub pubkey: &'a [u8],
    
    /// The lamports for the account
    pub lamports: u64,
    
    /// The Pubkey of the owner program account
    pub owner: &'a [u8],
    
    /// This account's data contains a loaded program
    pub executable: bool,
    
    /// The epoch at which this account will next owe rent
    pub rent_epoch: u64,
    
    /// The data held in this account
    pub data: &'a [u8],
    
    /// Monotonically increasing write version
    pub write_version: u64,
    
    /// Transaction that caused this update
    pub txn: Option<&'a SanitizedTransaction>,
}

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Transaction Notifications

Plugins are notified when transactions are processed with full execution metadata including:
  • Transaction signature
  • Execution status (success/failure)
  • Log messages
  • Account modifications
  • Compute units consumed

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Slot and Block Events

Track validator progress:
  • Slot notifications - When slots start and complete
  • Block metadata - Block hash, parent slot, rewards
  • Block commitment - Finalization status updates

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Configuration

Configure Geyser plugins in your validator startup: 
agave-validator \
  --geyser-plugin-config /path/to/plugin-config.json \
  # ... other validator flags
Plugin configuration file (plugin-config.json): 
{
  "libpath": "/path/to/libmy_geyser_plugin.so",
  "accounts_selector": {
    "accounts": ["*"],
    "owners": []
  },
  "transaction_selector": {
    "mentions": []
  }
}

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Building a Plugin

To create a Geyser plugin:
  1. Implement the GeyserPlugin trait
use agave_geyser_plugin_interface::geyser_plugin_interface::{
    GeyserPlugin, 
    ReplicaAccountInfoVersions,
    Result as PluginResult
};

#[derive(Default)]
pub struct MyGeyserPlugin {
    // Plugin state
}

impl GeyserPlugin for MyGeyserPlugin {
    fn name(&self) -> &'static str {
        "MyGeyserPlugin"
    }
    
    fn update_account(
        &self,
        account: ReplicaAccountInfoVersions,
        slot: u64,
        is_startup: bool,
    ) -> PluginResult<()> {
        // Handle account update
        Ok(())
    }
    
    fn notify_transaction(
        &self,
        transaction: ReplicaTransactionInfoVersions,
        slot: u64,
    ) -> PluginResult<()> {
        // Handle transaction notification
        Ok(())
    }
    
    // Implement other required methods...
}
  1. Export the plugin constructor
#[no_mangle]
#[allow(improper_ctypes_definitions)]
pub unsafe extern "C" fn _create_plugin() -> *mut dyn GeyserPlugin {
    let plugin = MyGeyserPlugin::default();
    let plugin: Box<dyn GeyserPlugin> = Box::new(plugin);
    Box::into_raw(plugin)
}
  1. Build as a dynamic library
[lib]
crate-type = ["cdylib"]

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Use Cases

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Real-time Indexing

Stream account and transaction data to databases for fast queries:
  • PostgreSQL indexers
  • Elasticsearch clusters
  • Custom data warehouses

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Analytics Pipelines

Feed blockchain data to analytics systems:
  • Stream to Kafka/RabbitMQ
  • Export to data lakes
  • Real-time dashboards

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Custom Business Logic

Build application-specific data pipelines:
  • Token balance tracking
  • NFT marketplace indexing
  • DeFi protocol monitoring
  • Custom alert systems

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Performance Considerations

Geyser plugins run in the validator process and can impact performance. Keep callbacks fast and non-blocking.
Best practices:
  • Use async processing with queues
  • Batch updates when possible
  • Handle errors gracefully to avoid validator crashes
  • Monitor plugin memory usage
  • Test thoroughly under load

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Plugin Lifecycle

  1. Load - Validator loads the plugin dynamic library on startup
  2. Initialize - on_load() called with configuration
  3. Runtime - Callbacks invoked as events occur
  4. Shutdown - on_unload() called when validator stops

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Error Handling

Plugins should handle errors gracefully:
  • Return PluginResult::Err for recoverable errors
  • Log errors for debugging
  • Avoid panics that could crash the validator

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Source Reference

The Geyser plugin interface is defined in:
  • geyser-plugin-interface/src/geyser_plugin_interface.rs
  • geyser-plugin-manager/src/ - Plugin loading and management

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Next Steps

RPC API

Alternative real-time data access via RPC subscriptions

WebSocket Methods

Subscribe to account and transaction updates via WebSocket