Can I add an individual user to space permissions who is not in a group with space permissions

[Theresa Reynolds]

I want to give view only space permissions to an external user who is not in any internal user groups that have permission to access the space.

[Nic Brough -Adaptavist-]

Yes, you can add individuals in the space permissions, and grant them only "use" permission (no create/edit, attach, comment, etc)

They will have to be in a group that is granted access to the product though (the global "can log in" group)