Salesforce Sub-domain

The Entity ID URI of Salesforce as Service Provider depends on whether you have a Salesforce sub-domain:

If you don't have a Salesforce sub-domain: If you have a Salesforce sub-domain:
https://saml.salesforce.com https://[sub-domain].salesforce.com where [sub-domain] is your your Salesforce sub-domain. For example, if your registered Salesforce sub-domain is acme, then your Entity ID URL would be https://acme.salesforce.com