> For the complete documentation index, see [llms.txt](https://docs.bloxroute.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.bloxroute.com/eth/sending-transactions/frontrunning-protection.md).

# Private Transactions

The **`blxr_private_tx`** endpoint allows users to send a single transaction that is added directly to the blocks generated by block builders.\
\
Private txs are automatically enrolled in the BackRunMe service and will pay back searchers a portion of the profit. The endpoint returns a transaction hash.

This service is available via both the **Cloud API** and **Gateway API**.

## Submission Endpoint

* Method: `blxr_private_tx`
* Endpoint: `api.blxrbdn.com` (Cloud API)
* Gateway API Endpoint: `127.0.0.1:28333/ws` (assumes WebSocket port 28333)
* Request type: *`HTTPS,WSS`*

### Parameters

| Parameter                      | Description                                                                                                                                                                                                                                                                                                                                         |
| ------------------------------ | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **`transaction`**              | *\[Mandatory]* Raw transaction bytes without **`0x`** prefix.                                                                                                                                                                                                                                                                                       |
| **`timeout`**                  | *\[Optional]* An integer value that represents the time, in seconds, needed to wait for a Private Transaction to be included in a block. If omitted, it defaults to 0. If **`timeout`** is not 0 and the transaction is not mined after the timeout value, it will be sent publicly. If the **`timeout`** is 0, no public transaction will be sent. |
| **`node_validation`**          | *\[Optional, default: false]* Transaction would be validated by a blockchain node, and Cloud-API returns an error message (e.g. "invalid sender" or "nonce too low") in case the raw transaction byte fails validation check.                                                                                                                       |
| **`priority_fee_refund`**      | \[Optional, default: false] Boolean. Set to `true` to join the [Priority Fee Refund Program](https://docs.bloxroute.com/eth/submit-bundles/priority-fee-refund). Required to receive a refund, together with `refund_recipient`.                                                                                                                    |
| **`refund_recipient`**         | *\[Optional]* A string representing the wallet address to receive refund when `priority_fee_refund` flag is enabled.                                                                                                                                                                                                                                |
| **`backrunme_reward_address`** | *\[Optional]* String – valid ETH address specifying where backrun rewards should be shared - See [Backrunme program](/backrunme-program/overview.md)                                                                                                                                                                                                |

### Example

{% tabs %}
{% tab title="HTTPS - Cloud API" %}

```bash
curl https://api.blxrbdn.com \
    --insecure \
    -X POST \
    -H "Content-Type: application/json" \
    -H "Authorization: <YOUR-AUTHORIZATION-HEADER>" \
    -d '{
         "id": "1", 
         "method": "blxr_private_tx", 
         "params": {
            "transaction": "f86b0184...e0b58219"
          }
        }'
```

{% endtab %}

{% tab title="wscat - Cloud API " %}

```bash
wscat -c wss://api.blxrbdn.com/ws --header "Authorization: <YOUR-AUTHORIZATION-HEADER>" --no-check
> {
	"jsonrpc": "2.0", 
	"id": 1, 
	"method": "blxr_private_tx", 
	"params": {
		"transaction": "f86b0184...e0b58219",
		"mev_builders": {
			"bloxroute": "",
			"flashbots": "",
			"beaverbuild": "",
			"all": ""
		}
	}
}
```

{% endtab %}
{% endtabs %}

#### Response

{% tabs %}
{% tab title="Cloud-API" %}

```bash
{
    "jsonrpc": "2.0", 
    "id": "1", 
    "result": "ffd59870844e5...bfa54a69"        
}    
```

{% endtab %}
{% endtabs %}


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