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Getting Started

To start searching on MEV-Share, you will need to connect to a matchmaker. A matchmaker receives transactions and bundles from users, and selectively shares information about transactions with searchers. When a searcher wants to include a transaction in their bundle, they use that transaction's hash, and the matchmaker replaces it with the original transaction before sending the bundle to a block builder.

Connect to Matchmaker‚Äč

Flashbots runs a matchmaker on Ethereum, to which you can connect today. The matchmaker has endpoints to receive transactions and bundles, as well as an SSE event stream endpoint which dispatches pending events/transactions to searchers.

The simplest way to connect to the Flashbots Matchmaker is to use a client library. For this guide, we'll refer to matchmaker-ts.

If you're coding in a language that doesn't yet have a matchmaker client library, you can send transactions & bundles directly with the JSON-RPC endpoint. To listen for transactions, all you need is an HTTP client. More details on that in the Event Stream page.

Add library to your project:

yarn add @flashbots/matchmaker-ts

Import library code (note ALL_CAPS variables are placeholders; replace with your own data):

import { Wallet, JsonRpcProvider } from "ethers"
import Matchmaker, {
ShareBundleParams,
PendingShareTransaction,
ShareTransactionOptions
} from "@flashbots/matchmaker-ts"

const provider = new JsonRpcProvider(RPC_URL)
const authSigner = new Wallet(FB_REPUTATION_PRIVATE_KEY, provider)
const matchmaker = Matchmaker.useEthereumMainnet(authSigner)

Connecting to Goerli:

const matchmaker = Matchmaker.useEthereumGoerli(authSigner)

Custom params (for developers):

// connect to matchmaker on mainnet
const matchmaker = new Matchmaker(authSigner, {
name: "mainnet",
chainId: 1,
streamUrl: "https://mev-share.flashbots.net",
apiUrl: "https://relay.flashbots.net",
})

See the repo documentation to learn more.


Continue reading on the next page to learn how to listen for pending transactions on MEV-Share.

A note for experienced searchers getting acquainted with MEV-Share

Searching on MEV-Share is different from searching on the mempool in that only certain parts of a transaction are shared with searchers. On the mempool, we can see all parts of a transaction, such as calldata and logs. But on MEV-Share, a transaction might only reveal its function selector, making a traditional arbitrage calculation infeasible (though this is not necessarily the common case).

That being said, existing strategies can still be employed. Users of MEV-Share have the option to share whichever parts of the transaction they deem appropriate, so strategies which use calldata and/or logs as input are still viable.

To maximally leverage the orderflow on MEV-Share, new searching strategies will have to be implemented to profitably include these transactions in your bundles. More specifically, you may have to reason about markets and/or blockchain state separately from the intra-block context of users' transactions, and leveraging data gleaned from mev-share transactions, probabilistically estimate the parameters of your MEV extraction strategy. A range of probable outcomes may be targeted in parallel, but this must be done efficiently, so as to maintain priority in the matchmaker's priority queues.