> For the complete documentation index, see [llms.txt](https://docs.blinklabs.xyz/blink/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.blinklabs.xyz/blink/arbitrum/searchers.md).

# Searchers

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

Please fill out our [searcher onboarding form](https://forms.gle/q7LLi3rkMVSZkyFYA) to get an API key to access the searcher websocket and to bid on transactions. Join our [telegram broadcast channel](https://t.me/+QZC4QzfdvH1jNzRi) for updates and announcements regarding our Arbitrum flow.

Our searcher backlog is quite large so we may not respond for several weeks.

By searching on our Arbitrum flow, you agree to our [searcher terms & conditions](/blink/ethereum/searchers/terms.md).

### Requirements

By participating in the Blink Arbitrum 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: [0x38939fe...](https://arbiscan.io/tx/0x38939fe506299fdfb1d8b1321cf427494fdca63ef48e7a9bee24ba439495a47a)

***

### WebSocket Subscriptions

**WebSocket Connection**

Connect to Blink's WebSocket endpoint:

```
wss://arbauction.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:

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

***

### Submitting Attribution Bundles

Submit bundles to:

```
https://arbauction.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):

```json
{
    "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.

***

### 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 submission time.

**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**

* Auction windows are variable. We recommend minimizing latency to achieve optimal backrun landing rates.
* We strongly recommend colocating in **AWS us-east-2** for optimal latency.

***

### Blink Monitoring

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

* Frontrunning or sandwiching of Blink transactions
* Searchers sending transactions without attribution
* Profit kickback percentage (must be > 75%)

Violations may result in:

* Reduced flow
* WebSocket delay
* Complete ban