Groups
A group is who a group-scoped event is about. A static group keeps a list you add to; a dynamic group holds whoever's attributes contain its filter, so nobody keeps it up. Beside the groups somebody keeps are temporary lists, picked by a person for one send: you can see them, but a key cannot change one and an event cannot name one. In the Political party pack a group is, for example, “Montserrado County”.
POSTAdd to a group
Requires groups:write. Up to 500 memberships or people — the group's own kind — in one call. Somebody already in it is not an error, so a sync can send its whole list every time. One id this instance has no record of, or one member of staff, refuses the lot before anything is written.
200 with added: how many were new. 400 on a dynamic group, which keeps no list, or for an unknown id or a member of staff, named. 409 on a temporary list.
One result: the same fields in every pack. Press Response on the sample to see one whole.
On failure the body is { error, code } instead.