Skip to content

XGA auction winners are granted future block space via a token, which is used with submission of transactions for inclusion in the beta block. Budding bidders can register themselves with the protocol to participate in beta block auctions. Thereupon custom implementations will be required to bid and submit transactions. Technical details are provided herein.

Technical Overview:

Full working examples are available for:



L1 Bridge

Fund L2 address by sending ETH to the L1 bridge address.

Deployed Address


Deployed Address (Testnet)



Deployed Address (Mainnet and Testnet)


Auction Contracts

Deployed Addresses


Deployed Addresses (Testnet)


Registering a bidder

Only registered bidders can participate in the auction. Operators can onboard new bidders through the contract.

To check for bidderId when registered, call IdMap on the contract:

function IdMap(address bidder) external view returns (uint8 id);

Packing a bid

Bids are packed by price, amount, bidderId

     * @dev Packed Bid details into a uint256 for submission.
     * @param bidPrice Price per item.
     * @param itemsToBuy Items to buy in the auction.
     * @param bidderId Id for bidder
     * @return packedBid for auction submission
    function packBid(uint256 bidPrice, uint256 itemsToBuy, uint256 bidderId)
        returns (uint256 packedBid);

Winning bid info

After an auction is closed, bidders can query their bid results:

     * @dev Retrieve information about a bidder after auction settlement.
     * @param slot The slot identifier of the auction.
     * @param bidder The address of the bidder for whom information is requested.
     * @return itemsBought The number of items bought by the bidder in the specified auction.
     * @return amountOwed The amount owed by the bidder for the items bought in the specified auction.
     * Requirements:
     * - The auction must have been settled.
     * - The provided `bidder` address must be valid and have participated in the auction.
    function getBidderInfo(uint256 slot, address bidder)
        returns (uint120 itemsBought, uint128 amountOwed);

Bidder Contracts

A minimal viable bidder is provided below. A more sophisticated fill or kill open bidder contract is provided.

/// SPDX-License-Identifier: UPL-1.0
pragma solidity ^0.8.25;

import {WETH} from "solmate/tokens/WETH.sol";
import {ERC6909} from "solmate/tokens/ERC6909.sol";

interface SettlementHouse {
    function submitBundle(uint256 slot, uint256 amount, bytes32[] calldata hashes) external;

/// @title MockBidder
contract MockBidder {
    uint256[] public bids;
    ERC6909 auctioneer;
    SettlementHouse house;
    WETH weth;

    constructor(WETH _weth, address _auctioneer, address settlement) {
        weth = _weth;
        auctioneer = ERC6909(_auctioneer);
        house = SettlementHouse(settlement);
        weth.approve(_auctioneer, type(uint256).max);

    function setBids(uint256[] memory newBids) public {
        bids = newBids;

    function getBid(uint256) external view returns (uint256[] memory packedBids) {
        return bids;

    function submit(uint256 slot, uint256 amount, bytes32[] calldata hashes) external {
        auctioneer.approve(address(house), slot, amount);
        house.submitBundle(slot, amount, hashes);

Submitting bundles

Beta Bundle RPC

  • Beta bundle RPC:

    • Description: Beta bundle submission RPC
    • URL:
    • Method: mev_sendBetaBundle
    • Parameters:
      • txs: List of txs as bundle e.g. [0x2323...,]
      • slot: slot number e.g. "11282389"
    • ChainId: 1
  • Beta bundle RPC (Testnet):

    • Description: Beta bundle submission RPC
    • URL:
    • Method: mev_sendBetaBundle
    • Parameters:
      • txs: List of txs as bundle e.g. [0x2323...,]
      • slot: slot number e.g. "11282389"
    • ChainId: 17000

Bundle JSON Requests and Responses

Example JSON request

    "jsonrpc": "2.0",
    "method": "mev_sendBetaBundle",
    "params": [
        "txs": [0x... ],
        "slot": "1001"
    "id": 8

Example JSON response

    "jsonrpc": "2.0",
    "id": 1,
    "method": "mev_sendBetaBundle",
    "result": "0x79e5cba7876f532218ac35a357209800be2362dd2e3f1e6dc5974698f0d7cee4",

Bundler Examples

  • Python bundler - employs a deployed bidder contract for continuous automated bidding, while listening for auction close event, then submits the bundle