FYI, the process at WunderGraph is a bit non standard in that they check references _before_ the interview and well before even an informal offer. From one of the job posts https://wundergraph.com/jobs/senior_golang_developer

The Process

    Intro with our CEO and CTO
    Culture fit call with the team
    Reference Check
    Small project / programming task (1 - 2h effort) to show off your proficiency
    Background Check
    Offer