diff --git a/spec/onyx-rest/view_spec.cr b/spec/onyx-rest/view_spec.cr
index aeef554..3c3efab 100644
--- a/spec/onyx-rest/view_spec.cr
+++ b/spec/onyx-rest/view_spec.cr
@@ -11,6 +11,15 @@ class Spec::View
 
     json foo: @foo, bar: @bar
 
+    json content_type: "application/json-a" do
+      builder do
+        field "foo", @foo
+        field "bar", @bar
+      end
+    end
+
+    json @foo.chars.map { |c| c.upcase.to_s }, content_type: "application/json-b"
+
     text "foo: #{@foo}, bar: #{@bar}"
 
     xml do
@@ -59,6 +68,22 @@ describe Onyx::HTTP::View do
     end
   end
 
+  describe "#render_to_application_json_a" do
+    it do
+      io = IO::Memory.new
+      view.render_to_application_json_a(io)
+      io.to_s.should eq %Q[{"foo":"baz","bar":42}]
+    end
+  end
+
+  describe "#render_to_application_json_b" do
+    it do
+      io = IO::Memory.new
+      view.render_to_application_json_b(io)
+      io.to_s.should eq %Q{["B","A","Z"]}
+    end
+  end
+
   describe "#render_to_text_plain" do
     it do
       io = IO::Memory.new
diff --git a/src/onyx-http/view.cr b/src/onyx-http/view.cr
index e90e535..316b252 100644
--- a/src/onyx-http/view.cr
+++ b/src/onyx-http/view.cr
@@ -112,7 +112,7 @@ module Onyx::HTTP::View
   # end
   # ```
   macro text(value, content_type = "text/plain", accept = {"text/plain"})
-    define_type_renderer(render_to_{{content_type.split("/").join("_").id}}, {{content_type}}, {{accept}}) do
+    define_type_renderer(render_to_{{content_type.split("/").map { |s| s.underscore.gsub(/-/, "_") }.join("_").id}}, {{content_type}}, {{accept}}) do
       io << ({{value}})
     end
   end
@@ -125,7 +125,7 @@ module Onyx::HTTP::View
   # end
   # ```
   macro template(template, content_type = "text/html", accept = {"text/html"})
-    define_type_renderer(render_to_{{content_type.split("/").join("_").id}}, {{content_type}}, {{accept}}) do
+    define_type_renderer(render_to_{{content_type.split("/").map { |s| s.underscore.gsub(/-/, "_") }.join("_").id}}, {{content_type}}, {{accept}}) do
       Kilt.embed("#{__DIR__}/#{{{template}}}", io)
     end
   end
@@ -141,7 +141,7 @@ module Onyx::HTTP::View
   #   ({{object}}).to_json(builder)
   # end
   # ```
-  macro json(object, content_type = "application/json", accept = {"application/json"})
+  macro json(object, content_type = "application/json", accept = {"application/json"}, &block)
     {% unless @type.methods.find { |m| m.name.stringify == "to_json" } %}
       def to_json(io : IO)
         ({{object}}).to_json(io)
@@ -152,8 +152,14 @@ module Onyx::HTTP::View
       end
     {% end %}
 
-    define_type_renderer(render_to_{{content_type.split("/").join("_").id}}, {{content_type}}, {{accept}}) do
-      ({{object}}).to_json(io)
+    define_type_renderer(render_to_{{content_type.split("/").map { |s| s.underscore.gsub(/-/, "_") }.join("_").id}}, {{content_type}}, {{accept}}) do
+      {% if block %}
+        {{object}} do |{{block.args.join(",").id}}|
+          {{block.body}}
+        end.to_json(io)
+      {% else %}
+        ({{object}}).to_json(io)
+      {% end %}
     end
   end
 
@@ -197,7 +203,7 @@ module Onyx::HTTP::View
       end
     {% end %}
 
-    define_type_renderer(render_to_{{content_type.split("/").join("_").id}}, {{content_type}}, {{accept}}) do
+    define_type_renderer(render_to_{{content_type.split("/").map { |s| s.underscore.gsub(/-/, "_") }.join("_").id}}, {{content_type}}, {{accept}}) do
       to_json(io)
     end
   end
@@ -251,7 +257,7 @@ module Onyx::HTTP::View
       end
     end
 
-    define_type_renderer(render_to_{{content_type.split("/").join("_").id}}, {{content_type}}, {{accept}}) do
+    define_type_renderer(render_to_{{content_type.split("/").map { |s| s.underscore.gsub(/-/, "_") }.join("_").id}}, {{content_type}}, {{accept}}) do
       to_xml(io)
     end
   end