Right now, the way Zapier works, it's no possible to check if a keygen user exists, create one if not, and continue with the workflow. (Their path system only allows branching, but not merging branches back together.)
One way around this would be to not have the "Create user" action fail if the user already exists,

or to add another action "Find or create user" which does just that.
Right now, the way Zapier works, it's no possible to check if a keygen user exists, create one if not, and continue with the workflow. (Their path system only allows branching, but not merging branches back together.)
One way around this would be to not have the "Create user" action fail if the user already exists,
or to add another action "Find or create user" which does just that.