Builder API Service

WHAT IT DOES

Builder API Service gives Ethereum validators, searchers, and developers a comprehensive interface for interacting with block builder APIs. It reads live data including builder API endpoint status, block builder registrations, submitted bundles, builder performance metrics, validator preferences, and block proposals. You can register with builder APIs, submit bundles for block inclusion, configure validator preferences, and monitor builder status. The tool shows you in real time whether builders are active, how many proposals are pending, what bundles have been submitted, and the last block processed—so you can optimize your builder relationships and maximize block proposal efficiency.

HOW TO USE

Connect your EVM wallet (must be the contract owner or authorized address). Enter the builder contract address, API endpoint URL, bundle data, and validator preference address. Use "Check builder status" to see active status, last block, and active proposals. Click "Register builder" to register a new builder endpoint. Use "Submit bundle" to send bundle data to the builder. "Set validator preference" configures which validators are used for proposals. "Query proposals" shows current active proposals. Each action generates a transaction you review and sign in your wallet.

TECHNICAL APPROACH

This tool interacts with builder API contracts using ethers v5.7.2. It calls registerBuilder(), submitBundle(), setValidatorPreference(), getBuilderStatus(), getActiveProposals(), and getLastBlock() on the builder contract to manage and query builder state. The tool validates endpoint URLs, bundle data format, and addresses before submission. It checks builder status by reading active state and last block number from the contract. For bundle submission, it sends the bundle data as calldata. All RPC calls are wrapped in a robust error handler that extracts the actual failure reason from Ethers error objects, digging three levels deep to avoid showing "[object Object]" when a transaction reverts. Transaction costing uses receipt.effectiveGasPrice post-EIP-1559 rather than tx.gasPrice, which overstates actual spend.

WHAT IT CANNOT SEE

This tool cannot guarantee builder honesty or bundle inclusion. It cannot detect off-chain builder collusion or manipulation. It cannot verify that a builder endpoint is actually operational or honest. It cannot simulate block proposals or predict which builder will accept a bundle. It cannot see builder internal decision-making or preference logic. It cannot detect whether a builder is censoring transactions or manipulating outcomes. The tool manages builder registrations and submissions, but it does not guarantee that builders will act honestly or that bundles will be included in blocks.

PLEASE NOTE

This tool supports EVM‑compatible chains only (Ethereum, Goerli, Sepolia, Arbitrum, Optimism, Polygon). Builder APIs are primarily used on Ethereum Mainnet and testnets. Solana, Tron, Starknet, SUI, TON, Aptos, Bitcoin, Cosmos, and XRP are not supported. This is a read‑write tool that requires signing transactions—always verify the builder contract address, API endpoint, bundle data, and preferences before approving. No contract addresses are hardcoded; you paste the contracts you are managing. The tool is free and open under the BotGentz PLAYBOOK‑C specification.