Private Transaction Bundle Submitter

WHAT IT DOES

Private Transaction Bundle Submitter is a specialized Developer Tools application that enables users to submit signed transaction bundles to private relay endpoints for confidential mempool submission. It reads the current mempool state, pending transaction queue, transaction nonce, gas price, and block timestamp to construct optimized bundles. The tool accepts multiple transactions with their target contract addresses, calldata, and value, then signs and submits them as a bundle to private relays like Flashbots or Bloxroute. It reads the user's balance and allowance to validate transaction feasibility before submission. The tool monitors bundle submission status, transaction receipts, and bundle inclusion status after submission. It supports configurable gas parameters, target block numbers, and bundle replacement transactions for resubmission. Users can submit bundles with strict transaction ordering guarantees, preventing front-running and sandwich attacks on their transactions.

HOW TO USE

Connect your wallet and select your network from the dropdown. Enter the private relay endpoint URL (e.g., Flashbots relay). Fill in the transaction details: target contract address, calldata in hex format, and value in ETH for each transaction in the bundle. At least one transaction is required; the second transaction is optional but enables multi-step operations. Configure gas parameters: set gas price in Gwei, gas limit, and optionally target a specific block number for submission. Review your bundle configuration—the tool will display the transactions in the order they will execute. Click "Submit Private Bundle" to sign and submit the bundle to the private relay. The tool displays the bundle hash, submission status, and inclusion block number once confirmed. The bundle is sent directly to the relay endpoint without entering the public mempool, reducing the risk of front-running.

BUNDLE CONSTRUCTION AND PRIVATE RELAY SUBMISSION ENGINE

The tool implements a robust bundle construction engine that signs and orders transactions for private relay submission. It reads the user's current nonce from the provider and assigns sequential nonces to each transaction in the bundle to ensure correct execution order. The tool validates each transaction's target address and calldata format, and constructs the transaction objects with appropriate gas parameters. For each transaction, the tool signs it using the wallet's signer, producing a raw signed transaction string. The bundle is then assembled as an array of signed transactions in the specified order. For relay submission, the tool constructs the bundle request with the following parameters: signed transactions array, target block number (optional), and bundle replacement parameters (optional). The tool sends the bundle request to the relay endpoint using HTTP POST with JSON encoding. It handles the relay's response, parsing the bundle hash and submission status. The tool also implements retry logic for bundle replacement—if a bundle is not included, it can resubmit with higher gas or adjusted parameters. For gas estimation, the tool uses the provider's fee data and applies a configurable multiplier to ensure the bundle is competitive. The tool also validates that each transaction's sender has sufficient balance to cover the value and gas costs before submission.

WHAT IT CANNOT SEE

This tool cannot verify that the bundle will be included in the next block or any specific block. It cannot detect if the bundle has been front-run, leaked, or exposed to the public mempool. It cannot guarantee that the private relay will not be compromised, censored, or manipulated. It cannot recover funds if the bundle fails, reverts, or contains invalid transactions. It cannot ensure that the bundle will be executed in the specified order if the relay reorders transactions. It cannot verify that the target contracts are safe, have not been exploited, or are free from bugs. It cannot provide financial, investment, or trading advice. It cannot guarantee that the bundle will not be censored or dropped by the relay. It cannot predict block inclusion time with certainty. It cannot verify that the bundle's transactions are optimal for the current mempool state. It cannot detect if the relay endpoint is malicious or compromised.

PLEASE NOTE

This tool supports EVM-compatible chains only. It requires an active RPC connection and a wallet with signing capabilities. The tool does not custodial funds or private keys. Always verify transaction calldata and target addresses before signing. Private relays charge fees or require API keys—check the relay's terms. Bundles are not guaranteed to be included; use with caution. The tool is for advanced users and developers; you bear full responsibility for bundle construction and submission.