Domain Checker is WordPress plugin that allows you to check for domain name availability using NameCheap API.
Simply download the latest release and upload the zip file under your WordPress dashboard at Plugins > Add New. Don’t forget to activate the plugin.
First, go to Settings > Domain Checker and enter your Namecheap Username, API User and API Key. Then, use this shortcode below to show the domain checker on WordPress posts/pages.
If you use Namecheap Sandbox environment, then domain name availability is not real. Domain names registered in real will be shown as available in the Sandbox, unless you register them in the sandbox environment.