Error using SharePoint REST API endpoint for creating a Modern Teams site: The parameter request does not exist in method CreateGroupEx - sharepoint

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I am trying to use the SharePoint REST API endpoint _api/GroupSiteManager/CreateGroupEx to create a SharePoint Modern Teams site
url: /_api/GroupSiteManager/CreateGroupEx
accept: application/json;odata.metadata=none
odata-version: 4.0
method: POST
body:
{
"request": {
"Title": "Communication Site 1",
"Url":"https://contoso.sharepoint.com/sites/commsite1",
"Lcid": 1033,
"ShareByEmailEnabled":false,
"Classification":"Low Business Impact",
"Description":"MyDescription",
"WebTemplate":"STS#3",
"SiteDesignId":"6142d2a0-63a5-4ba0-aede-d9fefca2c767",
"Owner":"owner#yourtenant.onmicrosoft.com"
}
}
I have proven my API process by creating a Modern Communication site with the endpoint /_api/SPSiteManager/create and "WebTemplate":"SITEPAGEPUBLISHING#0"
When I attempt to create the Modern Teams site I get the error:
Failed: {"error":{"code":"-1, Microsoft.SharePoint.Client.InvalidClientQueryException","message":{"lang":"en-US","value":"The parameter request does not exist in method CreateGroupEx."}}}

Answer 1

Try to update the request body like below:
body:{
"request": {
alias: "Communication Site 1",
displayName: "Communication Site 1",
isPublic: true,
optionalParams: {
Classification: "Low Business Impact",
CreationOptions: [`SPSiteLanguage:1033`,`implicit_formula_292aa8a00786498a87a5ca52d9f4214a_6142d2a0-63a5-4ba0-aede-d9fefca2c767`],
Description: "MyDescription",
Owners: "owner#yourtenant.onmicrosoft.com"
}
}
}
Also I have noticed that changing the Accept to below helps:
'Accept': 'application/json;odata.metadata=minimal'

Answer 2

It clearly complains about the "request" parameter, telling that there is no such parameter. Worked for me:
url: /_api/GroupSiteManager/CreateGroupEx
accept: application/json
method: POST
body: {
"alias": "CommunicationSite1",
"displayName": "Communication Site 1",
"isPublic": true,
"optionalParams": {
"CreationOptions": [
"SPSiteLanguage:1033",
"implicit_formula_292aa8a00786498a87a5ca52d9f4214a_6142d2a0-63a5-4ba0-aede-d9fefca2c767"
],
"Description": "MyDescription",
"Owners": ["owner#yourtenant.onmicrosoft.com"]
}
}
Some notes:
alias should not contain spaces (it is a part of url and email nickname)
I have no idea what the classification could be, just omited (your string does not seem work)
owners should be an array, not a string