# Searcher

### Introduction

Searchers can subscribe to transactions from the [Private Mempool](../../../streams/mempool/private-mempool/) to execute backrun strategies, and then send bid to BlockRazor RPC to win the backrun auction. 

Additionally, searchers can skip bundle subscriptions and directly send bundles to BlockRazor RPC. With the network acceleration service of the high-performance network, BlockRazor RPC can forward bundles to builders with minimal latency, eliminating the need to repeatedly connect to builder interfaces.



### RPC Endpoint

{% hint style="info" %}
Please keep the domain for subscribing to the bundle consistent with the domain for sending the bundle. For example, if subscribing to <mark style="color:$info;">https://jp-ethscutum.blockrazor.xyz/stream</mark>, then send the bundle to <mark style="color:$info;">https://jp-ethscutum.blockrazor.xyz</mark>
{% endhint %}

<table><thead><tr><th width="149.453125">Region</th><th>Endpoint</th></tr></thead><tbody><tr><td>Tokyo</td><td>https://jp-ethscutum.blockrazor.xyz</td></tr><tr><td>New York</td><td>https://us-ethscutum.blockrazor.xyz</td></tr></tbody></table>



### eth\_sendBid

{% hint style="info" %}
To protect private transactions, `eth_sendBid` is restricted to designated Searchers. Please [contact](https://discord.com/invite/qqJuwRb8Nh) us if you need to send a bid.
{% endhint %}

#### Request Parameter

<table><thead><tr><th width="121.43359375">Parameter</th><th width="123.98828125">Mandatory</th><th width="97.12109375">Format</th><th width="119.37890625">Example</th><th>Remark</th></tr></thead><tbody><tr><td>txs</td><td>Mandatory</td><td>[]string</td><td>["tx_hash", "rawTxHex"]</td><td><code>tx_hash</code> refers to the originator transaction in the  <a href="../../../streams/mempool/private-mempool/">Private Mempool</a>, while <code>rawTxHex</code> is the backrun transaction being constructed.<br>If the backrun target is a bundle, please fill in all <code>tx_hash</code> values from the bundle.</td></tr><tr><td>blockNumber</td><td>Optional</td><td>hex string</td><td>"0x102286B"</td><td>A hex-encoded block number indicating the latest valid block for the bundle. The default value is the current block number + 100.</td></tr></tbody></table>

#### Bid **mechanism**

BlockRazor will replace the `tx_hash` in the Bid with `rawTxHex`, and after adding `refundPercent` and `refundRecipient`, immediately forward it to the Builder for block inclusion.&#x20;

From the Builder's perspective, the Bid's value is determined by the backrun transaction’s `priority fee + coinbase.transfer()`. Since the `refundPercent` for the same originator transaction remains consistent, the Bid with the highest total value will be successfully included.

#### Request Example

**Backrun Originator Transaction**

```bash
curl https://eth.blockrazor.xyz \
  -X POST \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer <token>" \
  --data '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "eth_sendBid",
    "params": [
      {
        "txs": [
          "0x3a3c086bad1e765076986814939d2be70399e85ff75e4da8ec730aaf6ce3fea1",
          "0x02f86d0182149c808411e1a300830484e294fef10de0823f58df4f5f24856ab4274ededa6a5c8084c179306cc001a075d1f8fea39352c2da065aeef85be4b24789953f57a62ca7ad29b45bfc1e362aa043de44543083d0dafb80eaedd5764d6ef03336ff028ef02f238bccd5dfa9ece9"
        ],
        "blockNumber": "0x102286B"
      }
    ]
  }'
```

**Backrun Originator Bundle**

```bash
curl https://eth.blockrazor.xyz \
  -X POST \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer <token>" \
  --data '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "eth_sendBid",
    "params": [
      {
        "txs": [
          "0x3a3c086bad1e765076986814939d2be70399e85ff75e4da8ec730aaf6ce3fea1",
          "0x47816242f30167d1525a98801355f49370fc83049cb070d5d3ae9fd6c83d2d9d",
          "0x02f86d0182149c808411e1a300830484e294fef10de0823f58df4f5f24856ab4274ededa6a5c8084c179306cc001a075d1f8fea39352c2da065aeef85be4b24789953f57a62ca7ad29b45bfc1e362aa043de44543083d0dafb80eaedd5764d6ef03336ff028ef02f238bccd5dfa9ece9"
        ],
        "blockNumber": "0x102286B"
      }
    ]
  }'
```



### eth\_sendBundle

Searchers can also act as project builders to send raw bundles. For details, please refer to [Project Builder](project-builder.md).