What is a vendor portal is usually asked by someone who has just been shown one in a demo and is not sure what problem it solves. The short answer: it is a page where your suppliers see and update the parts of their own record you let them, and it exists so that the annual round of chasing insurance certificates and contact changes stops being your job.
It exists to move the chasing
The information that goes stale fastest is the information the supplier holds and you do not: its insurance certificate, its contact names, its remittance details. Without a portal, somebody in your business chases all of that once a year forever, and it is precisely the work that quietly does not happen. A portal turns your work into theirs.
The verification stays on your side
A portal that lets a supplier change bank details unchecked has automated the fraud rather than the chasing. The upload is theirs; the confirming call to a number you already held is still yours, and the record should show who made it and when. Any product that closes that loop by itself is selling you a liability.
It has to be one route in, not the only one
Some suppliers will use a portal and some will email a PDF forever. A record that is only current when every supplier logs in will never be current. Both routes have to land in the same place, with the same expiry date recorded, or the portal creates a two-tier record that is worse than having none.
Questions people ask about what is a vendor portal
What is a vendor portal?
A page where your suppliers view and update the parts of their own record you allow: contact details, insurance certificates, remittance information, and documents you have requested. It exists to stop you chasing.
Will small suppliers actually use one?
Some will and some will not, which is why it has to be one route rather than the only route. The value shows up on the suppliers who do use it, not on the ones who never will.
Should suppliers change bank details in the portal?
They can request it; you confirm out of band before anything is paid. Bank detail change is the most attacked field in small business payments and no portal should be allowed to close that loop alone.