> how to setup supertokens on US instance? Do I have just change configuration file and point to master database on Europe instance?
We don't support reading and writing from a different instances at the moment. This means:
You can run a SuperTokens instance in Europe, talking to the master MySQL instance in Europe. Your backend code (in both regions) will talk to that one ST instance (which is in Europe).
> From what I understood if blacklisting is disabled, supertokens won't query database on every request. Is it the case?
Yes. This is correct. Session verification for most requests will happen without any networking (even without needing to query the core). This means super, super fast session verifications.
In other cases (like when you create a new session, revoke one, or refresh one), the ST instance in Europe will be queried, which will be a little slow (for US region), but that is OK since these requests are relatively rare.