Every resource supports plain as well as JSON GET requests. JSON responses can be requested by setting the corresponding Accept header, i.e., Accept: application/json. myip.rs tries to identify whether a request is sent by CLI client and then only returns the plain response unless JSON is explicitly requested. In this way for example, a simple curl myip.rs/ retrieves your IP address. You can also add "/json" to any resource to force a JSON response regardless of the Accept header.
> curl myip.rs/
> wget -qO - myip.rs/tcp
> http -b myip.rs/host
> curl -H "Accept: application/json" myip.rs/ip
> wget -qO- --header=Accept:application/json myip.rs/tcp
> http -bj myip.rs/host