Is Staging Site Counted As A Site Activation

Nope, your staging site, local development site, or tests site won’t be counted as a site in your license.

If you are under a single site license, it should be fine to use your license key in another another site for staging/testing/development purposes as long as the domain matches these:

Here are the Top-level domains that are considered as dev or staging:

• *.dev
• *.dev.cc (DesktopServer)
• *.test
• *.local
• *.staging
• *.example
• *.invalid
• *.myftpupload.com (GoDaddy)
• *.cloudwaysapps.com (Cloudways)
• *.wpsandbox.pro (WPSandbox)
• *.ngrok.io (tunneling)
• *.mystagingwebsite.com (Pressable)
• *.tempurl.host (WPMU DEV)
• *.wpmudev.host (WPMU DEV)
• *.websitepro-staging.com (Vendasta)
• *.websitepro.hosting (Vendasta)
• *.instawp.xyz (InstaWP)

And here are the Subdomains that are considered as dev or staging:

• local.*
• dev.*
• test.*
• stage.*
• staging.*
• stagingN.* (SiteGround; N is an unsigned int)
• *.wpengine.com (WP Engine)
• dev-*.pantheonsite.io (Pantheon)
• test-*.pantheonsite.io (Pantheon)
• staging-*.kinsta.com (Kinsta)
• staging-*.kinsta.cloud (Kinsta)

And for localhost:

• localhost:* (any port)