What is vendor management software?
Vendor management software is the system that holds every supplier an organisation buys from — who they are, what they provide, and what contracts and spend trace back to them — so that "who do we depend on, and for what" has one answer instead of living in separate spreadsheets per department. At its simplest that's a directory: one record per vendor, not one per purchase order. Done well, it also tracks each vendor's standing — contract status, and how concentrated the organisation's spend or dependency is on that one supplier — because a directory only earns its keep if it also tells you something about exposure.
Vendor risk management software is the part of that discipline aimed specifically at exposure: which vendors would take a critical process or application down with them if they failed or ended the relationship tomorrow, and which capabilities the organisation is sourcing from only one supplier rather than several. It's a question that rarely gets asked until a vendor actually has an outage, because answering it ahead of time means linking a vendor record to everything that depends on it technically, not just contractually — the harder, less common half of vendor management software.