Your application may participate in user testing, referred to within the API as "experiments". To find out if the current user is part of an experiment, and to get the assigned group, you can make a call to the "me" object:
{ me { experiments(anonId: "anonId") { id name groups { id name } } } }
which will return something like the following:
{
"me": {
"experiments": [
{
"id": "05zy1a06d7cd5tj2r1p7m929jm",
"name": "Accept Button Placement",
"groups": [
{
"id": "05zy1a06d6p2vnyq0mgg4ng9wg",
"name": "control"
}
]
}
]
}
}
(note that, despite "groups" being an array, you will only ever be a member of one)
It is important to only fetch experiments if you will act on the data. Users are assigned to groups on fetch, and from then on assumed to be using the information given.