Confluence - How to create a space key? Can it be changed?

How do you create space keys? Can it be changed later on? Can two spaces have the same space key when they got two different space names?

When creating a new space, Confluence will suggest a unique space key as soon as you start typing the name of the space. You can edit this space key before you create the space.

Each space key must be unique and can contain any alphanumeric character, such as letters from A to Z and numbers from zero to nine. Special characters or spaces are not allowed. It can be an incredible 255 characters long!

Personal spaces always use their user’s name as the space key.

The space key cannot be changed after being created, so choose carefully!

You can watch our Video #46 of the Video Tutorial Series “Learn Atlassian Confluence” and read about the space key on this page of Atlassian’s original documentation.