diff --git a/lib/travis/api/app/responders/base.rb b/lib/travis/api/app/responders/base.rb
index 8849f553..5f463d9c 100644
--- a/lib/travis/api/app/responders/base.rb
+++ b/lib/travis/api/app/responders/base.rb
@@ -32,6 +32,10 @@ module Travis::Api::App::Responders
       endpoint.headers
     end
 
+    def apply
+      endpoint.content_type content_type
+    end
+
     def apply?
       resource && acceptable_format?
     end
diff --git a/lib/travis/api/app/responders/image.rb b/lib/travis/api/app/responders/image.rb
index 604094cf..d80d28e4 100644
--- a/lib/travis/api/app/responders/image.rb
+++ b/lib/travis/api/app/responders/image.rb
@@ -13,6 +13,10 @@ module Travis::Api::App::Responders
 
     private
 
+      def content_type
+        'image/png'
+      end
+
       def filename
         "#{root}/public/images/result/#{result}.png"
       end
diff --git a/lib/travis/api/app/responders/json.rb b/lib/travis/api/app/responders/json.rb
index 13065d0e..15388f6b 100644
--- a/lib/travis/api/app/responders/json.rb
+++ b/lib/travis/api/app/responders/json.rb
@@ -8,11 +8,17 @@ class Travis::Api::App
       end
 
       def apply
+        super
+
         halt result.to_json if result
       end
 
       private
 
+        def content_type
+          'application/json;charset=utf-8'
+        end
+
         def accepts_log?
           return true unless resource.is_a?(Log)
 
diff --git a/lib/travis/api/app/responders/plain.rb b/lib/travis/api/app/responders/plain.rb
index 2320b1e2..9d045478 100644
--- a/lib/travis/api/app/responders/plain.rb
+++ b/lib/travis/api/app/responders/plain.rb
@@ -14,17 +14,22 @@ module Travis::Api::App::Responders
     end
 
     def apply
+      super
+
       filename    = resource.id
       disposition = params[:attachment] ? 'attachment' : 'inline'
 
       headers['Content-Disposition'] = %(#{disposition}; filename="#{filename}")
 
-      endpoint.content_type 'text/plain'
       halt(params[:deansi] ? clear_ansi(resource.content) : resource.content)
     end
 
     private
 
+      def content_type
+        'text/plain'
+      end
+
       def clear_ansi(content)
         content.gsub(/\r\r/, "\r")
                .gsub(/^.*\r(?!$)/, '')
diff --git a/lib/travis/api/app/responders/xml.rb b/lib/travis/api/app/responders/xml.rb
index 9fa43fcf..e2137f4a 100644
--- a/lib/travis/api/app/responders/xml.rb
+++ b/lib/travis/api/app/responders/xml.rb
@@ -20,11 +20,17 @@ module Travis::Api::App::Responders
     end
 
     def apply
+      super
+
       halt TEMPLATE % data
     end
 
     private
 
+      def content_type
+        'application/xml;charset=utf-8'
+      end
+
       def data
         {
           name:     resource.slug,
diff --git a/spec/unit/responders/json_spec.rb b/spec/unit/responders/json_spec.rb
index eb2ffa33..37146d58 100644
--- a/spec/unit/responders/json_spec.rb
+++ b/spec/unit/responders/json_spec.rb
@@ -6,7 +6,7 @@ module Travis::Api::App::Responders
     end
 
     let(:request)  { stub 'request', params: {} }
-    let(:endpoint) { stub 'endpoint', request: request }
+    let(:endpoint) { stub 'endpoint', request: request, content_type: nil  }
     let(:resource) { stub 'resource' }
     let(:accept)   { stub 'accept entry', version: '2', params: {} }
     let(:options)  { { :accept => accept} }