diff --git a/src/compiler/crystal/tools/doc/constant.cr b/src/compiler/crystal/tools/doc/constant.cr
index 68e05ac6a36e..e028691dc4ae 100644
--- a/src/compiler/crystal/tools/doc/constant.cr
+++ b/src/compiler/crystal/tools/doc/constant.cr
@@ -25,10 +25,10 @@ class Crystal::Doc::Constant
     Highlighter.highlight value.to_s
   end
 
-  Item.def_to_json(
-    name: {nilable: false},
-    value: {nilable: true, stringify: true},
-    doc: {nilable: true},
-    summary: {nilable: true, property: :formatted_summary},
+  JSON.def_to_json(
+    name: true,
+    value: {converter: JSON::StringConverter},
+    doc: true,
+    summary: {converter: JSON::StringConverter},
   )
 end
diff --git a/src/compiler/crystal/tools/doc/generator.cr b/src/compiler/crystal/tools/doc/generator.cr
index fa70d828ad13..45f393789c7f 100644
--- a/src/compiler/crystal/tools/doc/generator.cr
+++ b/src/compiler/crystal/tools/doc/generator.cr
@@ -353,10 +353,10 @@ class Crystal::Doc::Generator
   end
 
   record RelativeLocation, filename : String, line_number : Int32, url : String? do
-    Item.def_to_json(
-      filename: {nilable: false},
-      line_number: {nilable: false},
-      url: {nilable: true}
+    JSON.def_to_json(
+      filename: true,
+      line_number: true,
+      url: true
     )
   end
   SRC_SEP = "src#{File::SEPARATOR}"
diff --git a/src/compiler/crystal/tools/doc/item.cr b/src/compiler/crystal/tools/doc/item.cr
index 56eaf056ed59..ef2b5abee8b9 100644
--- a/src/compiler/crystal/tools/doc/item.cr
+++ b/src/compiler/crystal/tools/doc/item.cr
@@ -6,68 +6,4 @@ module Crystal::Doc::Item
   def formatted_summary
     @generator.summary(self)
   end
-
-  macro def_to_json(type, properties)
-    Item.def_to_json(nil, {{properties}})
-  end
-
-  macro def_to_json(type, **properties)
-    Item.def_to_json({{type}}, {{properties}})
-  end
-
-  macro def_to_json(type, properties)
-    def to_json({% if type %}value : {{type.id}}, {% end %}json : ::JSON::Builder)
-      json.object do
-        {% for key, value in properties %}
-          {% keyid = (value[:property] || key).id %}
-          _{{keyid}} = {{ (type ? "value" : "self").id }}.{{keyid}}
-
-          {% unless value[:emit_null] %}
-            unless _{{keyid}}.nil?
-          {% end %}
-
-            json.field({{key.id.stringify}}) do
-              {% if value[:root] %}
-                {% if value[:emit_null] %}
-                  if _{{keyid}}.nil?
-                    nil.to_json(json)
-                  else
-                {% end %}
-
-                json.object do
-                  json.field({{value[:root]}}) do
-              {% end %}
-
-              {% if value[:converter] %}
-                if _{{keyid}}
-                  {{ value[:converter] }}.to_json(_{{keyid}}, json)
-                else
-                  nil.to_json(json)
-                end
-              {% elsif value[:stringify] %}
-                _{{keyid}}.to_s.to_json(json)
-              {% else %}
-                _{{keyid}}.to_json(json)
-              {% end %}
-
-              {% if value[:root] %}
-                {% if value[:emit_null] %}
-                  end
-                {% end %}
-                  end
-                end
-              {% end %}
-            end
-
-          {% unless value[:emit_null] %}
-            end
-          {% end %}
-        {% end %}
-      end
-    end
-  end
-
-  macro def_to_json(**properties)
-    Item.def_to_json(nil, {{properties}})
-  end
 end
diff --git a/src/compiler/crystal/tools/doc/json_converter.cr b/src/compiler/crystal/tools/doc/json_converter.cr
index c83f7c5b051e..7b47353ee64a 100644
--- a/src/compiler/crystal/tools/doc/json_converter.cr
+++ b/src/compiler/crystal/tools/doc/json_converter.cr
@@ -10,10 +10,10 @@ module Crystal::Doc
       end
     end
 
-    Item.def_to_json(
-      repository_name: {nilable: false},
-      body: {nilable: false},
-      program: {nilable: false}
+    JSON.def_to_json(
+      repository_name: true,
+      body: true,
+      program: true
     )
   end
 
@@ -26,42 +26,41 @@ module Crystal::Doc
       end
     end
 
-    Item.def_to_json(Type,
-      html_id: {nilable: false},
-      # json_path: {nilable: false},
-      kind: {nilable: true},
-      full_name: {nilable: false},
-      name: {nilable: false}
+    JSON.def_to_json(Type,
+      html_id: true,
+      kind: true,
+      full_name: true,
+      name: true
     )
 
-    Item.def_to_json(Crystal::Def,
-      name: {nilable: false},
-      args: {nilable: false, converter: JsonConverter},
-      double_splat: {nilable: true, converter: JsonConverter},
-      splat_index: {nilable: true},
-      yields: {nilable: true},
-      block_arg: {nilable: true, converter: JsonConverter},
-      return_type: {nilable: true, stringify: true},
-      visibility: {nilable: false, stringify: true},
-      body: {nilable: true, stringify: true},
+    JSON.def_to_json(Crystal::Def,
+      name: true,
+      args: {converter: JsonConverter},
+      double_splat: {converter: JsonConverter},
+      splat_index: true,
+      yields: true,
+      block_arg: {converter: JsonConverter},
+      return_type: {converter: JSON::StringConverter},
+      visibility: {converter: JSON::StringConverter},
+      body: {converter: JSON::StringConverter},
     )
 
-    Item.def_to_json(Crystal::Macro,
-      name: {nilable: false},
-      args: {nilable: false, converter: JsonConverter},
-      double_splat: {nilable: true, converter: JsonConverter},
-      splat_index: {nilable: true},
-      block_arg: {nilable: true, converter: JsonConverter},
-      visibility: {nilable: false, stringify: true},
-      body: {nilable: true, stringify: true},
+    JSON.def_to_json(Crystal::Macro,
+      name: true,
+      args: {converter: JsonConverter},
+      double_splat: {converter: JsonConverter},
+      splat_index: true,
+      block_arg: {converter: JsonConverter},
+      visibility: {converter: JSON::StringConverter},
+      body: {converter: JSON::StringConverter},
     )
 
-    Item.def_to_json(Crystal::Arg,
-      name: {nilable: false},
-      doc: {nilable: true},
-      default_value: {nilable: true, stringify: true},
-      external_name: {nilable: false, stringify: true},
-      restriction: {nilable: true, stringify: true},
+    JSON.def_to_json(Crystal::Arg,
+      name: true,
+      doc: true,
+      default_value: {converter: JSON::StringConverter},
+      external_name: {converter: JSON::StringConverter},
+      restriction: {converter: JSON::StringConverter},
     )
   end
 end
diff --git a/src/compiler/crystal/tools/doc/macro.cr b/src/compiler/crystal/tools/doc/macro.cr
index 8fd721a9f631..1c485a279c7d 100644
--- a/src/compiler/crystal/tools/doc/macro.cr
+++ b/src/compiler/crystal/tools/doc/macro.cr
@@ -93,16 +93,16 @@ class Crystal::Doc::Macro
     @generator.must_include? @macro
   end
 
-  Item.def_to_json(
-    id: {nilable: false},
-    html_id: {nilable: false},
-    name: {nilable: false},
-    doc: {nilable: true},
-    summary: {nilable: true, property: :formatted_summary},
-    abstract: {nilable: false, property: :abstract?},
-    args: {nilable: true, converter: JsonConverter},
-    args_string: {nilable: true, property: :args_to_s},
-    source_link: {nilable: true},
-    def: {nilable: false, property: :macro, converter: JsonConverter}
+  JSON.def_to_json(
+    id: true,
+    html_id: true,
+    name: true,
+    doc: true,
+    summary: {property: :formatted_summary},
+    abstract: {property: :abstract?},
+    args: {converter: JsonConverter},
+    args_string: {property: :args_to_s},
+    source_link: true,
+    def: {property: :macro, converter: JsonConverter}
   )
 end
diff --git a/src/compiler/crystal/tools/doc/method.cr b/src/compiler/crystal/tools/doc/method.cr
index 5e66c7a6ed71..9ca2022f17d0 100644
--- a/src/compiler/crystal/tools/doc/method.cr
+++ b/src/compiler/crystal/tools/doc/method.cr
@@ -203,16 +203,16 @@ class Crystal::Doc::Method
     !@def.args.empty? || @def.block_arg || @def.yields
   end
 
-  Item.def_to_json(
-    id: {nilable: false},
-    html_id: {nilable: false},
-    name: {nilable: false},
-    doc: {nilable: true},
-    summary: {nilable: true, property: :formatted_summary},
-    abstract: {nilable: false, property: :abstract?},
-    args: {nilable: true, converter: JsonConverter},
-    args_string: {nilable: true, property: :args_to_s},
-    source_link: {nilable: true},
-    def: {nilable: false, converter: JsonConverter}
+  JSON.def_to_json(
+    id: true,
+    html_id: true,
+    name: true,
+    doc: true,
+    summary: {property: :formatted_summary},
+    abstract: {property: :abstract?},
+    args: {converter: JsonConverter},
+    args_string: {property: :args_to_s},
+    source_link: true,
+    def: {converter: JsonConverter}
   )
 end
diff --git a/src/compiler/crystal/tools/doc/type.cr b/src/compiler/crystal/tools/doc/type.cr
index 7c145985eacb..02a695255047 100644
--- a/src/compiler/crystal/tools/doc/type.cr
+++ b/src/compiler/crystal/tools/doc/type.cr
@@ -773,35 +773,35 @@ class Crystal::Doc::Type
 
   delegate to_s, inspect, to: @type
 
-  Item.def_to_json(
-    html_id: {nilable: false},
-    path: {nilable: false},
-    # json_path: {nilable: false},
-    kind: {nilable: true},
-    full_name: {nilable: false},
-    name: {nilable: false},
-    abstract: {nilable: false, property: :abstract?},
-    superclass: {nilable: true, converter: JsonConverter},
-    ancestors: {nilable: false, converter: JsonConverter},
-    locations: {nilable: false},
-    repository_name: {nilable: false},
-    program: {nilable: false, property: :program?},
-    enum: {nilable: false, property: :enum?},
-    alias: {nilable: false, property: :alias?},
-    aliased: {nilable: true, property: :alias_definition, stringify: true},
-    const: {nilable: false, property: :const?},
-    constants: {nilable: false},
-    included_modules: {nilable: false, converter: JsonConverter},
-    extended_modules: {nilable: false, converter: JsonConverter},
-    subclasses: {nilable: false, converter: JsonConverter},
-    including_types: {nilable: false, converter: JsonConverter},
-    namespace: {nilable: true, converter: JsonConverter},
-    doc: {nilable: true},
-    summary: {nilable: true, property: :formatted_summary},
-    class_methods: {nilable: false},
-    constructors: {nilable: false},
-    instance_methods: {nilable: false},
-    macros: {nilable: false},
-    types: {nilable: false},
+  JSON.def_to_json(
+    html_id: true,
+    path: true,
+    # json_path: true,
+    kind: true,
+    full_name: true,
+    name: true,
+    abstract: {property: :abstract?},
+    superclass: {converter: JsonConverter},
+    ancestors: {converter: JsonConverter},
+    locations: true,
+    repository_name: true,
+    program: {property: :program?},
+    enum: {property: :enum?},
+    alias: {property: :alias?},
+    aliased: {property: :alias_definition, converter: JSON::StringConverter},
+    const: {property: :const?},
+    constants: true,
+    included_modules: {converter: JsonConverter},
+    extended_modules: {converter: JsonConverter},
+    subclasses: {converter: JsonConverter},
+    including_types: {converter: JsonConverter},
+    namespace: {converter: JsonConverter},
+    doc: true,
+    summary: {property: :formatted_summary},
+    class_methods: true,
+    constructors: true,
+    instance_methods: true,
+    macros: true,
+    types: true,
   )
 end