diff --git a/lib/ex_doc.ex b/lib/ex_doc.ex
index 9591ffed8..4c6f1d6bd 100644
--- a/lib/ex_doc.ex
+++ b/lib/ex_doc.ex
@@ -9,6 +9,19 @@ defmodule ExDoc do
 
     You can find more details about these options in the `ExDoc.CLI` module.
     """
+
+    @default %{
+      :formatter => "html",
+      :output => "./doc",
+      :source_ref => "master",
+      :retriever => ExDoc.Retriever,
+    }
+
+    @spec default(atom) :: term
+    def default(field) do
+      Map.fetch!(@default, field)
+    end
+
     defstruct [
       assets: nil,
       canonical: nil,
@@ -16,15 +29,16 @@ defmodule ExDoc do
       extra_section: nil,
       extras: [],
       filter_prefix: nil,
-      formatter: "html",
+      formatter: @default.formatter,
       formatter_opts: [],
       homepage_url: nil,
       logo: nil,
       main: nil,
-      output: "doc",
+      output: @default.output,
       project: nil,
-      retriever: ExDoc.Retriever,
+      retriever: @default.retriever,
       source_beam: nil,
+      source_ref: @default.source_ref,
       source_root: nil,
       source_url: nil,
       source_url_pattern: nil,
@@ -48,6 +62,7 @@ defmodule ExDoc do
        project: nil | String.t,
        retriever: :atom,
        source_beam: nil | String.t,
+       source_ref: nil | String.t,
        source_root: nil | String.t,
        source_url: nil | String.t,
        source_url_pattern: nil | String.t,
@@ -114,7 +129,7 @@ defmodule ExDoc do
   # Helpers
 
   defp normalize_options(options) do
-    pattern = options[:source_url_pattern] || guess_url(options[:source_url], options[:source_ref] || "master")
+    pattern = options[:source_url_pattern] || guess_url(options[:source_url], options[:source_ref] || ExDoc.Config.default(:source_ref))
     options = Keyword.put(options, :source_url_pattern, pattern)
 
     if is_bitstring(options[:output]) do
diff --git a/lib/mix/tasks/docs.ex b/lib/mix/tasks/docs.ex
index 3b1f1fea1..ca2cfe1cd 100644
--- a/lib/mix/tasks/docs.ex
+++ b/lib/mix/tasks/docs.ex
@@ -138,7 +138,7 @@ defmodule Mix.Tasks.Docs do
 
   defp get_formatters(options) do
     case Keyword.get_values(options, :formatter) do
-      [] -> options[:formatters] || ["html"]
+      [] -> options[:formatters] || [ExDoc.Config.default(:formatter)]
       values -> values
     end
   end
diff --git a/test/ex_doc_test.exs b/test/ex_doc_test.exs
index aff051510..482883dde 100644
--- a/test/ex_doc_test.exs
+++ b/test/ex_doc_test.exs
@@ -49,6 +49,20 @@ defmodule ExDocTest do
                  fn -> ExDoc.generate_docs project, version, options end
   end
 
+  test "default configuration" do
+    assert Map.get(%ExDoc.Config{}, :formatter) == "html"
+    assert ExDoc.Config.default(:formatter) == "html"
+
+    assert Map.get(%ExDoc.Config{}, :output) == "./doc"
+    assert ExDoc.Config.default(:output) == "./doc"
+
+    assert Map.get(%ExDoc.Config{}, :source_ref) == "master"
+    assert ExDoc.Config.default(:source_ref) == "master"
+
+    assert Map.get(%ExDoc.Config{}, :retriever) == ExDoc.Retriever
+    assert ExDoc.Config.default(:retriever) == ExDoc.Retriever
+  end
+
   test "version" do
     assert ExDoc.version =~ ~r{\d+\.\d+\.\d+}
   end