> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://partner.ninjatrader.com/connect/api/rest-api-endpoints/prices/initialize-clock/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://partner.ninjatrader.com/_mcp/server.

# Initialize Clock

POST https://demo.tradovateapi.com/v1/replay/initializeclock
Content-Type: application/json

### Set the inital date and time for a market replay session.

Using a WebSocket connected to the Tradovate Market Replay URL, we can start a Market Replay Session which will simulate a given timeframe as if it were happening live. Each replay session creates a new replay account which gets discarded at the end of the replay session.

```js

const URL = 'wss://replay.tradovateapi.com/v1/websocket'

const myMarketReplaySocket = new WebSocket(URL)

//simple WebSocket authorization procedure
myMarketReplaySocket.onOpen = function onOpen() {
    myMarketReplaySocket.send(`authorize\n0\n\n${accessToken}`)
})

const requestBody = {
    startTimestamp: new Date('2018-04-30').toJSON(),
    speed: 100, //100%, range is from 0-400%
    initialBalance: 50000 //account balance for replay session
}

myMarketReplaySocket.send(`replay/initializeclock\n1\n\n${JSON.stringify(requestBody)}`)

myMarketReplaySocket.addEventListener('message', msg => {
    const datas = JSON.parse(msg.data.slice(1))
    if(datas) {
        datas.forEach(({i, d}) => {
            if(i && i === 1) { //sent id is 1, response id will be 1
                console.log(d) //=> { ok: true }
            }
        })
    }
})

```

Reference: https://partner.ninjatrader.com/connect/api/rest-api-endpoints/prices/initialize-clock

## Authentication

- `Authorization` header (bearer token, required) — Bearer authentication of the form `Bearer <token>`, where token is your auth token.

## Request

### Body (application/json)

This endpoint expects an InitializeClock.

- `startTimestamp` (datetime, required)
- `speed` (integer, required)
- `initialBalance` (double, optional)

## Response

### 200

SimpleResponse

- `ok` (boolean, required)
- `errorText` (string, optional) — Non-empty if the request failed

## Examples

**Request**

```json
{
  "startTimestamp": "2024-01-15T09:30:00Z",
  "speed": 1
}
```

**Response**

```json
{
  "ok": true,
  "errorText": "string"
}
```

**SDK Code**

```python
import requests

url = "https://demo.tradovateapi.com/v1/replay/initializeclock"

payload = {
    "startTimestamp": "2024-01-15T09:30:00Z",
    "speed": 1
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.json())
```

```javascript
const url = 'https://demo.tradovateapi.com/v1/replay/initializeclock';
const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: '{"startTimestamp":"2024-01-15T09:30:00Z","speed":1}'
};

try {
  const response = await fetch(url, options);
  const data = await response.json();
  console.log(data);
} catch (error) {
  console.error(error);
}
```

```go
package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://demo.tradovateapi.com/v1/replay/initializeclock"

	payload := strings.NewReader("{\n  \"startTimestamp\": \"2024-01-15T09:30:00Z\",\n  \"speed\": 1\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}
```

```ruby
require 'uri'
require 'net/http'

url = URI("https://demo.tradovateapi.com/v1/replay/initializeclock")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"startTimestamp\": \"2024-01-15T09:30:00Z\",\n  \"speed\": 1\n}"

response = http.request(request)
puts response.read_body
```

```java
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.Unirest;

HttpResponse<String> response = Unirest.post("https://demo.tradovateapi.com/v1/replay/initializeclock")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"startTimestamp\": \"2024-01-15T09:30:00Z\",\n  \"speed\": 1\n}")
  .asString();
```

```php
<?php
require_once('vendor/autoload.php');

$client = new \GuzzleHttp\Client();

$response = $client->request('POST', 'https://demo.tradovateapi.com/v1/replay/initializeclock', [
  'body' => '{
  "startTimestamp": "2024-01-15T09:30:00Z",
  "speed": 1
}',
  'headers' => [
    'Authorization' => 'Bearer <token>',
    'Content-Type' => 'application/json',
  ],
]);

echo $response->getBody();
```

```csharp
using RestSharp;

var client = new RestClient("https://demo.tradovateapi.com/v1/replay/initializeclock");
var request = new RestRequest(Method.POST);
request.AddHeader("Authorization", "Bearer <token>");
request.AddHeader("Content-Type", "application/json");
request.AddParameter("application/json", "{\n  \"startTimestamp\": \"2024-01-15T09:30:00Z\",\n  \"speed\": 1\n}", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
```

```swift
import Foundation

let headers = [
  "Authorization": "Bearer <token>",
  "Content-Type": "application/json"
]
let parameters = [
  "startTimestamp": "2024-01-15T09:30:00Z",
  "speed": 1
] as [String : Any]

let postData = JSONSerialization.data(withJSONObject: parameters, options: [])

let request = NSMutableURLRequest(url: NSURL(string: "https://demo.tradovateapi.com/v1/replay/initializeclock")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "POST"
request.allHTTPHeaderFields = headers
request.httpBody = postData as Data

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error as Any)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()
```