Document using the sandbox

Author: horgh

README.md

@@ -294,6 +294,13 @@ service:
 $client = new Client(42, 'abcdef123456', ['en'], ['host' => 'geolite.info']);
 ```
 
+To call the Sandbox GeoIP2 web service instead of the production GeoIP2 web
+service:
+
+```php
+$client = new Client(42, 'abcdef123456', ['en'], ['host' => 'sandbox.maxmind.com']);
+```
+
 After creating the client, you may now call the method corresponding to a
 specific endpoint with the IP address to look up, e.g.:
 
@@ -321,7 +328,9 @@ use GeoIp2\WebService\Client;
 // Replace "42" with your account ID and "license_key" with your license
 // key. Set the "host" to "geolite.info" in the fourth argument options
 // array to use the GeoLite2 web service instead of the GeoIP2 web
-// service.
+// service. Set the "host" to "sandbox.maxmind.com" in the fourth argument
+// options array to use the Sandbox GeoIP2 web service instead of the
+// production GeoIP2 web service.
 $client = new Client(42, 'abcdef123456');
 
 // Replace "city" with the method corresponding to the web service that

src/WebService/Client.php

@@ -68,7 +68,12 @@ class Client implements ProviderInterface
      *                           * `host` - The host to use when querying the web
      *                           service. To query the GeoLite2 web service
      *                           instead of the GeoIP2 web service, set the
-     *                           host to `geolite.info`.
+     *                           host to `geolite.info`. To query the Sandbox
+     *                           GeoIP2 web service instead of the production
+     *                           GeoIP2 web service, set the host to
+     *                           `sandbox.maxmind.com`. The sandbox allows you to
+     *                           experiment with the API without affecting your
+     *                           production data.
      *                           * `timeout` - Timeout in seconds.
      *                           * `connectTimeout` - Initial connection timeout in seconds.
      *                           * `proxy` - The HTTP proxy to use. May include a schema, port,