Customers who want to slowly migrate their accelerator storefronts to Spartacus require some features to synchronise session state from one another. This requires some modifications on both the accelerator side as well as the Spartacus side. In order to support this model, we'll cover the Spartacus side, with the assumption that customers will follow a best practice guide (or potentially a code base from services) that can be applied on the backend.

The following session state must be shared cross Accelerator and Spartacus:

• Access token, JSESSIONID vs OAuth token (Sync user login from Accelerator to Spartacus #12285)
• Cart ID (Sync cart from Accelerator to Spartacus - whoami #12511)
• Selected Language, Currency, Point of Service (Sync site context Accelerator to Spartacus - whoami #12509)
• Routing - which are Spartacus and which are Accelerator (Support routing from Accelerator to Spartacus #12292)
• Global Messages (e.g. messages stored in Spring MVC Model vs Spartacus ngrx store) (Sync Global Messages from accelerator to Spartacus and visa versa #12387)

The assumption with this features is that both storefront applications run under the same domain, so that there's no issues with cross domain policies. It is to be expected that users will navigate back and forth from Accelerator to Spartacus pages all the time.