I don't know about the US but in Europe, charging is well specified. The typical standards are Type 2 for AC charging and CCS for DC charging and the European T

I don't know about the US but in Europe, charging is well specified. The typical standards are Type 2 for AC charging and CCS for DC charging and the European Teslas implement those. The Superchargers are fully CCS-compatible. This was demonstrated recently, when the authentication system on one Supercharger site failed and the Superchargers would happily charge cars of any brand at no cost. The news quickly spread and there were videos of a wide variety of cars charging at the Superchargers. Actually, they seemed to be more stable than some third party charging stations. Tesla did however fix that problem on the next day :p.