Pfizer vaccination and proof thereof

My research shows that travelers from the US need only proof of vaccination and the passenger locator form. Have you done the questionnaire here https://einreisecheck.admin.ch/check?

Firstly, is your trip this year?

When I flew there two weeks ago the only place I had to show proof of vaccination was at check-in at the airport stateside in my case in New York. United Airlines calls this documents verification. I could not check-in otherwise. The check of proof of vaccination is pretty much a brief glance as there will have been thousands of people flying in line ahead and then more behind you in line. I did register with the Swiss Health Department at the link to the site Laurel provided and printed those documents out, but when I arrived at Zurich the Passport Control immigration officer did not collect it or ask to see it and just asked like in normal times "purpose of your visit" and I always answer "I am on vacation." No one asked to see any documents other than my passport the entire time I was in Switzerland. Flying back you will show to the airline proof of a negative Covid test. If your airline is up to speed with complying with USA federal government rules currently you will not get a boarding pass back until the airline verifies your paper document showing a negative test. United lets you upload proof 72 hours before but they still need to see the physical copy.