 <p>You might be able to do this using a Base model such as:</p> <pre><code>@GET("mypath") Call&lt;MyBaseModel&lt;List&lt;MyModel&gt;&gt;&gt; getData(); </code></pre> <p>implement the Callback in the fragment as</p> <pre><code>Callback&lt;MyBaseModel&lt;List&lt;?&gt;&gt;&gt; </code></pre> <p>An example of an MyBaseModel would be:</p> <pre><code>public class MyBaseModel&lt;Data&gt; { private String page; private Data[] results; public String getPage() { return page; } public Data[] getResults() { return results; } } </code></pre> <p>The onResponse should return the:</p> <pre><code> Callback&lt;MyBaseModel&lt;?&gt;&gt; </code></pre> <p>then just check if the result is an instance of your model using 'instanceOf'</p>