This is a free DNS service that offers a unique feature of providing a simple domain name for every IP address. This makes it easy to test and access local network applications. For example, if your local server's IP address is 192.168.0.10, you can use the domain name 192-168-0-10.he3.app to access it. He3.app is extremely simple and convenient to use, making it particularly useful in development and testing environments.