### Answer --- The

data-agent-version

attribute is optional—if unset, it uses the latest version. [(1) ]() To find the version number for your chat agent, you can use the Get Chat Agent Versions API endpoint:

javascript
import Retell from 'retell-sdk';

const client = new Retell({
  apiKey: 'YOUR_RETELL_API_KEY',
}) ;

const chatAgentResponses = await client.chatAgent.getVersions('16b980523634a6dc504898cda492e939') ;
console.log(chatAgentResponses) ;

[(2) ]() This returns an array of all versions for that agent. Each version object includes a

version

field (integer) that you can use for

data-agent-version

. Example widget setup with a specific version:

html
<script
  id="retell-widget"
  src="<https://dashboard.retellai.com/retell-widget.js%22>
  data-public-key="key_xxxxxxxxxxxxxxxxxxxxx"
  data-agent-id="agent_xxxxxxxxxxxxxxxxxxx"
  data-agent-version="0"
></script>

[(1) ]()

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

​ To learn more, see the sources I considered: [[1] Retell Website Widget](https://docs.retellai.com/deploy/chat-widget) [[2] Get Chat Agent Versions](https://docs.retellai.com/api-references/get-chat-agent-versions) ​

### Answer That URL is an API endpoint template. Replace

{agent_id}

with your actual chat agent ID. Using the SDK (recommended) :

javascript
import Retell from 'retell-sdk';

const client = new Retell({
  apiKey: 'YOUR_RETELL_API_KEY',
}) ;

const chatAgentResponse = await client.chatAgent.create({
  response_engine: { llm_id: 'llm_234sdertfsdsfsdf', type: 'retell-llm' },
}) ;
console.log(chatAgentResponse.agent_id) ;

[(1) ]() The

agent_id

returned (e.g.,

oBeDLoLOeuAbiuaMFXRtDOLriTJ5tSxD

) is what you'd use in the endpoint URL. Making the API call: You need to include your API key in the Authorization header with format

Bearer YOUR_RETELL_API_KEY

. So the full request would be: - Method: GET - URL: ` - Header:

Authorization: Bearer YOUR_RETELL_API_KEY

Your agent ID can be found in your Retell dashboard when viewing your chat agent, or from the response when you created the agent.

​ To learn more, see the sources I considered: [[1] Create Chat Agent](https://docs.retellai.com/api-references/create-chat-agent) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer ### Answer The

Authorization header required

error means your API request is missing the authentication header. [(1) ]() You need to include your API key in the request headers with this format:

Authorization: Bearer YOUR_RETELL_API_KEY

[(2) ]() If using cURL or a REST client:

Authorization: Bearer YOUR_RETELL_API_KEY

If using the SDK (recommended) :

javascript
import Retell from 'retell-sdk';
const client = new Retell({
  apiKey: 'YOUR_RETELL_API_KEY',
}) ;

[(3) ]() You can find your API key in the Retell dashboard. [(1) ]()

​ To learn more, see the sources I considered: [[1] "Authorization header required"](https://discord.com/channels/1186424376300679209/1417963292327936101) [[2] Create Phone Call](https://docs.retellai.com/api-references/create-phone-call) [[3] List Calls](https://docs.retellai.com/api-references/list-calls) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

Thanks for the feedback, glad I was helpful.