diff --git a/README.md b/README.md
index d46c5c11..2410febf 100644
--- a/README.md
+++ b/README.md
@@ -475,8 +475,8 @@ urls.each do |url|
   end
 end
 
-# => "[404] not found error with url: https://httpbin.org/status/404  (Halite::ClientError)"
-# => "[500] internal server error error with url: https://httpbin.org/status/500?foo=bar  (Halite::ServerError)"
+# => "[404] not found error with url: https://httpbin.org/status/404 (Halite::Exception::ClientError)"
+# => "[500] internal server error error with url: https://httpbin.org/status/500?foo=bar (Halite::Exception::ServerError)"
 # => ""
 ```
 
diff --git a/spec/halite/error_spec.cr b/spec/halite/error_spec.cr
new file mode 100644
index 00000000..346668e4
--- /dev/null
+++ b/spec/halite/error_spec.cr
@@ -0,0 +1,54 @@
+require "../spec_helper"
+
+describe Halite::Exception do
+  describe "#APIError" do
+    it "should initial without arguments" do
+      error = Halite::APIError.new
+      error.message.should be_nil
+      error.status_code.should be_nil
+      error.status_message.not_nil!.should eq "unknown error"
+    end
+
+    it "should initial with message only" do
+      message = "foobar"
+
+      error = Halite::APIError.new(message)
+      error.message.not_nil!.should eq message
+      error.status_code.should be_nil
+      error.status_message.not_nil!.should eq "foobar error"
+    end
+
+    it "should initial with message and status_code" do
+      message = "foobar"
+      status_code = 400
+
+      error = Halite::APIError.new(message, status_code)
+      error.message.not_nil!.should eq message
+      error.status_code.not_nil!.should eq status_code
+      error.status_message.not_nil!.should eq "bad request error"
+    end
+
+    it "should initial with full arguments" do
+      message = "foobar"
+      status_code = 400
+      uri = URI.parse("https://www.example.com/get/foobar")
+
+      error = Halite::APIError.new(message, status_code, uri)
+      error.message.not_nil!.should eq message
+      error.status_code.not_nil!.should eq status_code
+      error.uri.not_nil!.should eq uri
+      error.status_message.not_nil!.should eq "bad request error with url: #{uri}"
+    end
+
+    it "should initial without message" do
+      status_code = 400
+      uri = URI.parse("https://www.example.com/get/foobar")
+
+      error = Halite::APIError.new(nil, status_code, uri)
+      error.message.not_nil!.should eq "#{status_code} bad request error with url: #{uri}"
+      error.status_code.not_nil!.should eq status_code
+      error.uri.not_nil!.should eq uri
+      error.status_message.not_nil!.should eq "bad request error with url: #{uri}"
+    end
+  end
+end
diff --git a/src/halite/error.cr b/src/halite/error.cr
index f5dae132..3e489c69 100644
--- a/src/halite/error.cr
+++ b/src/halite/error.cr
@@ -49,19 +49,28 @@ module Halite
     class APIError < ResponseError
       getter uri
       getter status_code
-      getter status_message
+      getter status_message : String? = nil
 
       def initialize(@message : String? = nil, @status_code : Int32? = nil, @uri : URI? = nil)
+        @status_message = build_status_message
         if status_code = @status_code
-          status_message = [HTTP::Status.new(status_code).description.to_s.downcase]
-          status_message << "error"
-          status_message << "with url: #{@uri.not_nil!}" if @uri
-
-          @message ||= "#{status_code} #{status_message.join(" ")} "
+          @message ||= "#{status_code} #{@status_message}"
         end
 
         super(@message)
       end
+
+      private def build_status_message : String
+        String::Builder.build do |io|
+          if status_code = @status_code
+            io << "#{HTTP::Status.new(status_code).description.to_s.downcase} error"
+          else
+            io << "#{@message || "unknown"} error"
+          end
+
+          io << " with url: #{@uri}" if uri = @uri
+        end.to_s
+      end
     end
 
     # 4XX client error