Storing customer IDs

To associate visitors’ subsequent sessions with their customer ID, you need to persistently store each CUID (consolidated user ID) on your server and pass it back to Optimizely the next time the customer visits your website. Otherwise, if you specify new every time, or for every new session, Optimizely creates a new CUID for each visit/session and cannot relate visits by the same customer.

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Note

A CUID identifies a user/device and should not be deleted at the end of session. A session ID, on the other hand, identifies a session: you need to request a new one for each session, and expire a session ID after four hours of inactivity.