Tesorio integrates with Salesforce using REST APIs. The integration requires a Connected App to be created within Salesforce. The data we import from Salesforce are:

Accounts
One-way sync of account data into Tesorio. Account data is matched with Customers only if a custom field containing the internal id of the customer record from the ERP system is present. 

Contacts
One-way sync of all contacts into Tesorio. Contacts associated with Accounts are linked with customers automatically. If an account has custom fields which are lookups of contacts, they will also come over as contacts within Tesorio.

Notes

One-way sync of customer notes originating from Tesorio can be pushed back into Salesforce. Notes will appear on the Salesforce Account under Notes and Attachments.