eth_sendDeterministicBundle

Submit a bundle for deterministic placement relative to watched addresses. The builder monitors the watched addresses during block construction and places the bundle once all of them have been touched at least once.

This is useful for strategies that depend on specific addresses having been touched — for example, executing after a DEX pool rebalances or after a lending protocol's state changes.

Requires the X-Flashbots-Signature header.

Parameters

Extends eth_sendBundle with an additional watchedAddresses field:

Field	Type	Required	Description
txs	string[]	Yes	Array of signed transactions as 0x-prefixed RLP-encoded hex strings
blockNumber	string	Yes	Target block number as a hex string (e.g. "0x1234567")
watchedAddresses	string[]	Yes	Addresses to watch for state changes. The bundle is placed after the last transaction that modifies any of these addresses.
minTimestamp	number	No	Minimum block timestamp (Unix seconds) for inclusion
maxTimestamp	number	No	Maximum block timestamp (Unix seconds) for inclusion
revertingTxHashes	string[]	No	Tx hashes allowed to revert without invalidating the bundle
droppingTxHashes	string[]	No	Tx hashes that, if already included on-chain, cause the bundle to be dropped
replacementUuid	string	No	UUID to enable bundle replacement
replacementNonce	number	No	Monotonically increasing nonce for replacement ordering
refundPercent	number	No	Percentage (0–100) of builder profit to refund to refundRecipient
refundRecipient	string	No	Address that receives the refund payment

Request

{
  "jsonrpc": "2.0",
  "method": "eth_sendDeterministicBundle",
  "params": [{
    "txs": ["0x02f8..."],
    "blockNumber": "0x137f8a0",
    "watchedAddresses": [
      "0x88e6A0c2dDD26FEEb64F039a2c41296FcB3f5640",
      "0xC36442b4a4522E871399CD717aBDD847Ab11FE88"
    ]
  }],
  "id": 1
}

Response

{
  "jsonrpc": "2.0",
  "result": {
    "bundleHash": "0xabcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890"
  },
  "id": 1
}

Field	Type	Description
bundleHash	string	0x-prefixed bundle hash. Use with eureka_getBundleStats to track inclusion.

Placement Behavior

• The builder waits until all watched addresses have been touched at least once, then attempts to place the bundle.

• If the bundle execution fails, the builder may reattempt placement after additional state changes to the watched addresses.

• If none of the watched addresses are touched by other transactions, the bundle is not included in the block.

Notes

• Bundle replacement and cancellation work the same as with eth_sendBundle — use replacementUuid to replace or call eth_cancelBundle to cancel.

• The bundle is only eligible for the specified blockNumber and is discarded after that block is built.