How to find the my salesforce.com instance?
its possible to find the instance details after logged in salesforce and its indicated to browsers address bar (see the screenshot):
In this case, the instance is ap1, but it could also be ap2, ap3, na1, na2, eu1, eu2 etc (based on the region like asia, europe, US, etc).
If you are using My Domain, you can’t see the instance name by looking at the browser’s address bar. so you can find the instance name using the below url and Enter your domain name on the Domain Lookup here to find out on which instance your org is on:
Note: in that above url, just enther the domain name instead of the entire url to get results with the domain lookup tool (e.g. use “mydomain” instead of “mydomain.my.salesforce.com”)