When OnRent is interlinked to Xero, do I need to be logged into Xero to use OnRent?

The simple answer is no.

OnRent stores the connection details required for interacting with your Xero account, this connection will take place when required and will not require you to log into the Xero solution (there could be a slight delay whilst OnRent logs into Xero for you).

For Example:

Posting an invoice or an invoice batch to Xero. Selecting to do so will trigger the OnRent solution to establish a connection to the interlinked Xero account and transfer the selected invoices/invoice batch.

Provided there are not any problems, the invoice/invoice batch will be sent to Xero, appear in Xero and marked as having been posted within OnRent.

If there are any issues you will receive an email advising you of this.