I seem to have misplaced my CDC card with my Covid vaccination records. Locally, I exclusively use the New York State Excelsior Pass, which is well understood here and pulls digital records from the NY database. I can also print out verification from the City. However, I do have a few questions

1) does anyone have any experience in using one state’s vaccine passport app / system in another state? For example, has anyone use an Excelsior Pass type platform in California or other states that require vaccination to enter certain venues?

2) Are non CDC card verification methods accepted for international travel?