As you are working with REST based service, change your web.config like below-
<configuration>
<system.servicemodel>
<behaviors>
<servicebehaviors>
<behavior name="mexBehaviour">
<servicemetadata httpgetenabled="true" />
</behavior>
</servicebehaviors>
<endpointbehaviors>
<behavior name="endPtBehaviour">
<webhttp />
</behavior>
</endpointbehaviors>
</behaviors>
<services>
<service name="TestService.Service1" behaviorconfiguration="mexBehaviour">
<endpoint address="" binding="webHttpBinding" behaviorconfiguration="endPtBehaviour" contract="TestService.IService1" />
<endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" />
<host>
<baseaddresses>
<add baseaddress="http://localhost/TestService/Service1.svc" />
</baseaddresses>
</host>
</service>
</services>
</system.servicemodel>
<system.web>
<compilation debug="true" />
</system.web>
</configuration>