diff --git a/src/radix/node.cr b/src/radix/node.cr
index 2512327..28e83cf 100644
--- a/src/radix/node.cr
+++ b/src/radix/node.cr
@@ -27,10 +27,10 @@ module Radix
   # # => [3, 2, 1]
   # ```
   class Node
-    getter :key
-    getter? :placeholder
-    property! :payload
-    property :children
+    getter key : String
+    getter? placeholder : Bool
+    property! payload
+    property children : Array(Node)
 
     # Returns the priority of the Node based on it's *key*
     #
@@ -54,7 +54,7 @@ module Radix
     # Node.new(":query").priority
     # # => 1
     # ```
-    getter :priority
+    getter priority : Int32
 
     # Instantiate a Node
     #
diff --git a/src/radix/result.cr b/src/radix/result.cr
index 8064d8e..d58fc0f 100644
--- a/src/radix/result.cr
+++ b/src/radix/result.cr
@@ -13,8 +13,8 @@ module Radix
   # A Result is also used recursively by `Tree#find` when collecting extra
   # information like *params*.
   class Result
-    getter :params
-    getter! :payload
+    getter params
+    getter! payload
 
     # :nodoc:
     def initialize
@@ -35,7 +35,7 @@ module Radix
     # result.found?
     # # => true
     # ```
-    def found?
+    def found? : Bool
       payload? ? true : false
     end
 
@@ -60,7 +60,7 @@ module Radix
     # result.key
     # # => ""
     # ```
-    def key
+    def key : String
       return @key if @key
 
       key = String.build { |io|
diff --git a/src/radix/tree.cr b/src/radix/tree.cr
index 709b764..fd44954 100644
--- a/src/radix/tree.cr
+++ b/src/radix/tree.cr
@@ -30,7 +30,7 @@ module Radix
     # Returns the root `Node` element of the Tree.
     #
     # On a new tree instance, this will be a placeholder.
-    getter :root
+    getter root : Node
 
     def initialize
       @root = Node.new("", placeholder: true)
@@ -397,7 +397,7 @@ module Radix
     end
 
     # :nodoc:
-    private def deprecation(message)
+    private def deprecation(message : String)
       STDERR.puts message
       STDERR.flush
     end