You can activate Link Whisper on development sites, even if you’re at the activation limit. The sites need to be on a development related subdomain, provided by your hosting provider or need to be on a .dev, .local, or .test domain.
The currently supported subdomains are:
Link Whisper’s licensing also supports the staging site systems of wpengine and cloudways.
If Link Whisper doesn’t activate on your dev or staging site, please contact Link Whisper Support. We’ll look into the problem and work to add support for your site.