How to add members to a Group using Microsoft Graph API - azure-active-directory

Question

How do I add Members to a Group via Microsoft Graph API?
According to documentation for adding Member to a particular Group, it requires the call below:
POST https://graph.microsoft.com/v1.0/groups/{id}/members/$ref
Content-type: application/json
Content-length: 30
{
"#odata.id": "https://graph.microsoft.com/v1.0/users/{id}"
}
My questions lies in this API:
https://graph.microsoft.com/v1.0/groups/{id}/members/$ref
{id} => the group id,
members => adding members to the group
Now where is the users/members data/parameter to be added or posted?
Is it "#odata.id": "https://graph.microsoft.com/v1.0/users/{id}"?
Do I post #odata.id values as a member/users parameter when adding a member to a group?

Answer 1

That is correct. What you're technically passing is an ODATA Reference (ref$) to the user object within Active Directory rather than just an id.
To illustrate, lets take this fictitious user:
{
"#odata.context": "https://graph.microsoft.com/v1.0/$metadata#users/$entity",
"id": "48d31887-5fad-4d73-a9f5-3c356e68a038",
"businessPhones": [
"[phone]"
],
"displayName": "Megan Bowen",
"givenName": "Megan",
"jobTitle": "Auditor",
"mail": "MeganB#M365x214355.onmicrosoft.com",
"mobilePhone": null,
"officeLocation": "12/1110",
"preferredLanguage": "en-US",
"surname": "Bowen",
"userPrincipalName": "MeganB#M365x214355.onmicrosoft.com"
}
If we wanted to add Megan to the a Group with an id of 02bd9fd6-8f93-4758-87c3-1fb73740a315 the call would look like this:
POST https://graph.microsoft.com/v1.0/groups/02bd9fd6-8f93-4758-87c3-1fb73740a315/members/$ref
Content-type: application/json
{
"#odata.id": "https://graph.microsoft.com/v1.0/users/MeganB#M365x214355.onmicrosoft.com"
}

Answer 2

It is also working when passing user Id:
POST url: https://graph.microsoft.com/v1.0/groups/{group_id}/members/$ref
Content-type: application/json
Content string: {"#odata.id": "https://graph.microsoft.com/v1.0/users/{user_id}"}
group_id - group object id
user_id - user object id