Hello,
The SNTC portal is available only to customers who have a Smart Services contract; and contains a lot more than just the ability to pull information about Cisco Security Vulnerabilities. You will have your inventory typically loaded via a CSPC or a third party collector; and then multiple reports are available based on the device and configuration information.
The PSIRT OpenVuln API is a RESTful API that allows customers to obtain Cisco Security Vulnerability information in different machine-consumable formats. It is available to any customer who has registered on cisco.com. Using this information you would have to combine that into your own tools that then audit your device configuration and types. SNTC portal has these tools already developed for you.
HTH
HTH
