Searchers

Searching on Base works a bit differently to Ethereum as there is no builder market.

Please reach out via [e-mail] or @Adamblink on telegram to get an API key to access the searcher websocket and to bid on transactions. Join our telegram broadcast channel for updates and announcements regarding our Base flow.

By searching on our Base flow, you agree to our searcher terms & conditions.

Requirements

By participating in the Blink Base FCFS auction, searchers agree to the following:

• No frontrunning of any kind. Sandwiching or any other form of frontrunning will result in an immediate ban.

• Self-submission to the sequencer. Searchers are responsible for submitting both the target transaction and their own backrun transaction directly to the sequencer. Blink does not submit on your behalf.

• Attribution via eth_sendBundle. Searchers must send an eth_sendBundle request to Blink for attribution purposes. The bidWei field is accepted but ignored — it does not affect ordering.

• Profit kickback of at least 75%. Searchers must send at least 75% of their profits to the address below as a native ETH transfer within the backrun transaction.

Kickback address: 0x743be0db30148336A3DB479f19d4e1828b293869

Example payment transaction: 0x4860d8e...

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WebSocket Subscriptions

Please reach out via [e-mail] to get set up with an API key.

WebSocket Connection

Connect to Blink's WebSocket endpoint:

wss://baseauction.blinklabs.xyz/ws/v1/{$API_KEY}

Transaction Subscription

The V1 WebSocket requires an explicit subscription to begin receiving transaction data. Send the following message after connecting:

{
    "method": "eth_subscribe",
    "params": ["blink_partialPendingTransactions"]
}

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Submitting Attribution Bundles

Submit bundles to:

https://baseauction.blinklabs.xyz/v1/{$API_KEY}

Bundles are submitted using the eth_sendBundle RPC call. The first element must be the target transaction hash; subsequent elements are your raw backrun transaction(s):

{
    "id": 1,
    "jsonrpc": "2.0",
    "method": "eth_sendBundle",
    "params": [
        {
            "txs": [
                "0xTargetTxHash",  // Target transaction hash (required)
                "0xRawBackrunHex"  // Your backrun transaction in raw hex format (required)
            ],
            "bidWei": "0"          // Ignored in V1 — include any value for compatibility
        }
    ]
}

The bundle must contain at least two transactions. The bidWei field is parsed for compatibility but has no effect on auction ordering or outcome.

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Auction Mechanics

How it works

• Blink broadcasts pending transactions to connected searchers via WebSocket.

• Searchers submit their backrun transaction directly to the sequencer alongside the target transaction. This results in a FCFS auction.

• Searchers also send an eth_sendBundle to Blink for attribution tracking.

• Transactions are ordered on-chain by the sequencer based on priority fee. Set your backrun priority fee equal to the target transaction's priority fee — transactions with a higher priority fee will result in ejection from the searcher pool.

Profit Kickback

• Send at least 75% of your profit as a native ETH transfer to 0x743be0db30148336A3DB479f19d4e1828b293869 within your backrun transaction.

• This allows Blink to pass profits through to originator sources.

Timing and Inclusion

• Each auction window is approximately 50ms. Late backruns will likely revert on-chain due to flashblock timing.

• We strongly recommend colocating in AWS us-east-1 for optimal latency.

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Blink Monitoring

Blink actively monitors for rule violations and will take action accordingly:

• Frontrunning or sandwiching of Blink transactions

• Searchers sending directly to the sequencer without attribution

• Profit kickback percentage (must be > 75%)

Violations may result in:

• Reduced flow

• WebSocket delay

• Complete ban