curl --request GET \
  --url https://{cluster}.voucherify.io/management/v1/projects/{projectId}/users \
  --header 'X-Management-Id: <api-key>' \
  --header 'X-Management-Token: <api-key>'

{
  "object": "list",
  "data_ref": "data",
  "data": [
    {
      "id": "user_FgEAjOw6riObJdy81s2yZXdqZNiAV1pM",
      "login": "name@youremaildomain.com",
      "email": "name@youremaildomain.com",
      "first_name": "Sammy",
      "last_name": "Jones",
      "projects": {
        "proj_9KeAhZB1": "USER",
        "proj_npnFzPr9": "USER",
        "proj_pEP3NO9s": "USER",
        "proj_zsPdrUIw": "ADMIN"
      },
      "is_owner": false
    },
    {
      "id": "user_11sYvPrOj3XE573FO1cAzzk1p4k92wLL",
      "login": "name@youremaildomain.com",
      "email": "name@youremaildomain.com",
      "first_name": "Alex",
      "last_name": "Smith",
      "projects": {
        "proj_3CNHbOe0": "ADMIN"
      },
      "is_owner": true
    }
  ],
  "total": 2
}