Last week, I launched a marketplace (https://whobal.com) for buying and selling side-projects. Now I am trying to add business ownership verification and need your input to choose the right method. Here are the validation methods I am considering:

1. HTTP-based - Ask sellers to upload a file in website root directory.

2. DNS-based - Ask seller to add a DNS record like TXT.

Personally, I would prefer DNS-based method as it is easier to detect and I have already done something similar in another project. But I am confused whether users will be able to update DNS or not.

If you were a seller, what would you to prefer and why?

Many thanks.