Bundle & New RPC Methods

New RPC methods in Kora v2.2.0-beta — Jito bundles, version, and bundle fee estimation.

These methods are available starting in v2.2.0-beta.1. Enable them in your kora.toml under [kora.enabled_methods].

getVersion

Retrieves the Kora server version information.

JSON-RPC Request

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "getVersion",
  "params": {}
}

JSON-RPC Response

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "version": "2.2.0-beta.6"
  }
}

cURL Example

curl -X POST http://localhost:8080 \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","id":1,"method":"getVersion","params":{}}'

TypeScript SDK

const result = await client.getVersion();
console.log('Kora version:', result.version);

Configuration

[kora.enabled_methods]
get_version = true

estimateBundleFee

Calculates the combined fee for multiple transactions in a bundle. Useful for determining the total cost before signing and submitting a bundle.

Note: Transaction plugins (e.g., gas_swap) are not executed during fee estimation. Plugins only run during signing flows (signBundle, signAndSendBundle).

JSON-RPC Request

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "estimateBundleFee",
  "params": {
    "transactions": [
      "base64EncodedTransaction1",
      "base64EncodedTransaction2"
    ],
    "fee_token": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v"
  }
}

Parameters

Parameter	Type	Required	Description
`transactions`	string[]	Yes	Array of base64-encoded transactions (max 5)
`fee_token`	string	Yes	Token mint for fee calculation

JSON-RPC Response

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "total_fee_in_lamports": "15000",
    "total_fee_in_token": "150",
    "fee_token": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
    "transaction_fees": [
      {
        "fee_in_lamports": "5000",
        "fee_in_token": "50"
      },
      {
        "fee_in_lamports": "10000",
        "fee_in_token": "100"
      }
    ]
  }
}

cURL Example

curl -X POST http://localhost:8080 \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "estimateBundleFee",
    "params": {
      "transactions": ["base64Tx1", "base64Tx2"],
      "fee_token": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v"
    }
  }'

TypeScript SDK

const estimate = await client.estimateBundleFee({
  transactions: [base64Tx1, base64Tx2, base64Tx3],
  fee_token: 'EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v',
});
console.log('Total fee:', estimate.total_fee_in_lamports, 'lamports');
console.log('Total fee in token:', estimate.total_fee_in_token);

Configuration

[kora.enabled_methods]
estimate_bundle_fee = true

[kora.bundle]
enabled = true

signBundle

Signs multiple transactions as a bundle without submitting them to the network. Use this when you want to handle bundle submission to Jito yourself.

This method is protected by reCAPTCHA when configured. Include the x-recaptcha-token header if your server has reCAPTCHA enabled.

When transaction plugins are enabled (e.g., gas_swap), each transaction in the bundle is validated against the plugin rules before signing.

Lighthouse Fee Payer Protection

When Lighthouse protection is enabled, Kora adds a balance assertion instruction to the last transaction in the bundle. This protects the fee payer from drainage attacks by ensuring the balance doesn't drop below expected levels after all bundle transactions complete.

Important: Since Lighthouse modifies the transaction message, any pre-existing client signatures on the last transaction become invalid. Clients must re-sign after receiving the modified bundle back from Kora.

signBundle → client receives modified txs → client re-signs last tx → client sends bundle

JSON-RPC Request

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "signBundle",
  "params": {
    "transactions": [
      "base64EncodedTransaction1",
      "base64EncodedTransaction2",
      "base64EncodedTransaction3"
    ],
    "signer_key": "3Z1Ef7YaxK8oUMoi6exf7wYZjZKWJJsrzJXSt1c3qrDE"
  }
}

Parameters

Parameter	Type	Required	Description
`transactions`	string[]	Yes	Array of base64-encoded transactions (max 5)
`signer_key`	string	No	Specific signer to use (defaults to pool selection)
`transactions_to_sign`	number[]	No	Indices of transactions to sign (defaults to all)

JSON-RPC Response

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "signed_transactions": [
      "base64EncodedSignedTransaction1",
      "base64EncodedSignedTransaction2",
      "base64EncodedSignedTransaction3"
    ],
    "signer_pubkey": "3Z1Ef7YaxK8oUMoi6exf7wYZjZKWJJsrzJXSt1c3qrDE"
  }
}

cURL Example

curl -X POST http://localhost:8080 \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "signBundle",
    "params": {
      "transactions": ["base64Tx1", "base64Tx2"],
      "signer_key": "3Z1Ef7YaxK8oUMoi6exf7wYZjZKWJJsrzJXSt1c3qrDE"
    }
  }'

TypeScript SDK

const result = await client.signBundle({
  transactions: [base64Tx1, base64Tx2, base64Tx3],
  signer_key: koraSignerAddress,
});
console.log('Signed transactions:', result.signed_transactions);

Partial Bundle Signing

Use transactions_to_sign to sign only specific transactions in the bundle:

// Only sign transactions at index 0 and 2
const result = await client.signBundle({
  transactions: [tx1, tx2, tx3, tx4],
  transactions_to_sign: [0, 2],
});
// tx1 and tx3 are signed by Kora, tx2 and tx4 remain unchanged

Configuration

[kora.enabled_methods]
sign_bundle = true

[kora.bundle]
enabled = true

signAndSendBundle

Signs and submits a bundle of up to 5 transactions to Jito's block engine. All transactions in the bundle execute atomically and sequentially — either all succeed or none do.

This method is protected by reCAPTCHA when configured. Include the x-recaptcha-token header if your server has reCAPTCHA enabled.

When transaction plugins are enabled (e.g., gas_swap), each transaction in the bundle is validated against the plugin rules before signing.

Note: Lighthouse fee payer protection does not apply to this method. Since bundles are sent immediately, adding a Lighthouse assertion would invalidate existing client signatures. If you need Lighthouse protection, use signBundle and handle Jito submission yourself after re-signing.

JSON-RPC Request

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "signAndSendBundle",
  "params": {
    "transactions": [
      "base64EncodedTransaction1",
      "base64EncodedTransaction2",
      "base64EncodedTransaction3"
    ],
    "signer_key": "3Z1Ef7YaxK8oUMoi6exf7wYZjZKWJJsrzJXSt1c3qrDE"
  }
}

Parameters

Parameter	Type	Required	Description
`transactions`	string[]	Yes	Array of base64-encoded transactions (max 5)
`signer_key`	string	No	Specific signer to use (defaults to pool selection)
`transactions_to_sign`	number[]	No	Indices of transactions to sign (defaults to all)

JSON-RPC Response

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "bundle_uuid": "8f4a3b2c-1d5e-6f7a-8b9c-0d1e2f3a4b5c",
    "signed_transactions": [
      "base64EncodedSignedTransaction1",
      "base64EncodedSignedTransaction2",
      "base64EncodedSignedTransaction3"
    ],
    "signer_pubkey": "3Z1Ef7YaxK8oUMoi6exf7wYZjZKWJJsrzJXSt1c3qrDE"
  }
}

cURL Example

curl -X POST http://localhost:8080 \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "signAndSendBundle",
    "params": {
      "transactions": ["base64Tx1", "base64Tx2"],
      "signer_key": "3Z1Ef7YaxK8oUMoi6exf7wYZjZKWJJsrzJXSt1c3qrDE"
    }
  }'

TypeScript SDK

const { bundle_uuid } = await client.signAndSendBundle({
  transactions: [base64Tx1, base64Tx2, base64Tx3],
  signer_key: koraSignerAddress,
});
console.log('Bundle submitted:', bundle_uuid);

Configuration

[kora.enabled_methods]
sign_and_send_bundle = true

[kora.bundle]
enabled = true

[kora.bundle.jito]
block_engine_url = "https://mainnet.block-engine.jito.wtf"

Note: When using bundles with Jito tips, ensure allow_transfer = true is set in [validation.fee_payer_policy.system] so the Kora signer can pay the tip.