# sendTransactionMessage

### sendTransactionMessage RPC Method <a href="#send-transaction-rpc-method" id="send-transaction-rpc-method"></a>

<mark style="color:green;">`POST`</mark> <https://sol-rpc.kolibr.io/>\
Submit a Solana transaction **message** (unsigned) to the block engine. Unlike `sendTransaction`, this method accepts a `solana.Transaction.Message` rather than a full signed transaction, and does **not** broadcast the transaction on-chain.<br>

**Additional URL Query Parameters**

<table><thead><tr><th width="236">Name</th><th>Description</th></tr></thead><tbody><tr><td><strong><code>rev_recv</code> (required)</strong></td><td>The address that will receive arbitrage payments in SOL.</td></tr></tbody></table>

**Body Parameters**

<table><thead><tr><th width="236">Name</th><th>Description</th></tr></thead><tbody><tr><td>params[0] <strong>(required)</strong></td><td>encoded message. A string containing the Solana transaction message serialized and encoded in base64 or base58.</td></tr><tr><td>params[1].encoding <strong>(optional)</strong></td><td>If omitted, the server tries base64 first, then base58.</td></tr><tr><td>params[1].expectedSubmitDelay <strong>(optional)</strong></td><td>Expected delay in milliseconds before the transaction is submitted on-chain by the block engine.</td></tr></tbody></table>

**Headers**

<table><thead><tr><th width="237">Name</th><th>Description</th></tr></thead><tbody><tr><td><code>Authorization</code> (optional)</td><td><p>An optional parameter, represented by a GUID string. While not required for basic operations, it is necessary for accessing premium features like the <code>subsidy</code> mode and enables higher rate limits.</p><p>To obtain an <code>Authorization</code> GUID, users must sign up in app.kolibrio.xyz</p></td></tr></tbody></table>

**Request Example**

{% tabs %}
{% tab title="curl" %}

```json
curl https://sol-rpc.kolibr.io/?rev_recv=DVz9Ryo4vUpizkpFoaUGGU4y5guc2bcBFSFAJvjQVmz5 \
  -X POST \
  -H "Content-Type: application/json" \
  -H "Authorization: 123e4567-e89b-12d3-a456-426614174000" \
  -d '
  {
  "jsonrpc": "2.0",
  "id": 1,
  "method": "sendTransactionMessage",
  "params": [
    "<encoded message>",
    {
      "encoding": "base58",
      "expectedSubmitDelay": 200
    }
  ]
}
'
```

{% endtab %}
{% endtabs %}

**Response Example**

{% tabs %}
{% tab title="200" %}

```json
### Success
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "ok"
}

### Error
{
  "jsonrpc": "2.0",
  "id": 1,
  "error": {
    "code": -32002,
    "message": "<error description>"
  }
}
```

{% endtab %}
{% endtabs %}