I also don't understand this: Everyone with the right domain can ssh-in the vm?

Edit: Answered below, thank you.

You ssh in with any key, and it asks you for an email to verify. You're then at a exe.dev console.

There are a couple different link patterns:

  exe.dev ▶ doc sharing
  Sharing (sharing) - press q to exit
                                                                                                                                                                                                                                                 
  You can share your VM's HTTP port (see the http proxy documentation /proxy) with your friends. There are three mechanisms:                                                                                                                     
                                                                                                                                                                                                                                                 
  1. Make the HTTP proxy public with share set-public <vm>. To point the proxy                                                                                                                                                                   
  at a different port inside the VM, run share port <vm> <port> first.                                                                                                                                                                           
  Marking it public lets anyone access the server without logging in.                                                                                                                                                                            
  2. Add specific e-mail addresses using share add <vm> <email>. This will                                                                                                                                                                       
  send the recipient an e-mail. They can then log into exe.dev with that e-mail,                                                                                                                                                                 
  and access https://vmname.exe.xyz/.                                                                                                                                                                                                            
  3. Create a share link with share add-link <vm>. The generated                                                                                                                                                                                 
  link will allow anyone access to the page, after they register and login.                                                                                                                                                                      
  Revoking the link (which can be done with the remove-link command)                                                                                                                                                                             
  does not revoke their access, but you can remove users who are already                                                                                                                                                                         
  part of the share using share remove <vm> <email>.