SendGrid API key
If a SendGrid API key is provided, VSys will contact SendGrid directly to query the results of e-mails sent using that key's account and a Teammate if provided. This is very efficient, very fast, and does not rely on an external server to track these events.
Note that only e-mails sent by the Standalone E-mail Robot version 126.96.36.1998+ and VSys One version 188.8.131.520+ capture the specific ID codes of outbound messages; e-mails sent by older versions of these tools cannot have their results retrieved.
Without a SendGrid API key
When using SendGrid for e-mail delivery, SendGrid posts status messages about each outgoing e-mail to a central server. These status messages can be "E-mail delivered", "Opened", "Marked as spam", etc. This scheduled task queries those messages and updates the status and logs for each outgoing e-mail in VSys.