# Create or update a user group user assignment

Endpoint: POST /buyers/{buyerID}/usergroups/assignments
Version: 1.0.448.36393
Security: OAuth2

## Path parameters:

  - `buyerID` (string, required)
    ID of the buyer.

## Request fields (application/json):

  - `UserGroupID` (string, required)

  - `UserID` (string, required)

## Response 4XX fields (application/json):

  - `StatusCode` (integer)
    Example: "404"

  - `ErrorCode` (string)
    Example: "NotFoundError"

  - `Message` (string)
    Example: "Object not found"

  - `Data` (object)
    Example: {"ObjectType":"","ObjectID":""}


## Response 204 fields