diff --git a/spec/webmock_spec.cr b/spec/webmock_spec.cr
index 77bbe82..aba8d8c 100644
--- a/spec/webmock_spec.cr
+++ b/spec/webmock_spec.cr
@@ -126,7 +126,7 @@ describe WebMock do
   it "stubs and calls block for response" do
     WebMock.wrap do
       WebMock.stub(:post, "www.example.com").with(body: "Hello!").to_return do |request|
-        headers = HTTP::Headers.new.merge!({ "Content-length" => "6" })
+        headers = HTTP::Headers.new.merge!({"Content-length" => "6"})
         HTTP::Client::Response.new(418, body: request.body.to_s.reverse, headers: headers)
       end
 
@@ -329,6 +329,120 @@ describe WebMock do
     end
   end
 
+  it "contains registered stubs on failure" do
+    WebMock.wrap do
+      WebMock.stub(:get, "https://test.example.com")
+      begin
+        HTTP::Client.get("https://www.example.com/")
+      rescue ex : WebMock::NetConnectNotAllowedError
+        ex.message.not_nil!.strip.should eq(
+          <<-MSG
+          Real HTTP connections are disabled. Unregistered request: GET https://www.example.com/ with headers {"Connection" => "close", "Host" => "www.example.com"}
+
+          You can stub this request with the following snippet:
+
+          WebMock.stub(:get, "https://www.example.com/").
+            to_return(body: "")
+
+          Registered request stubs:
+
+          stub(:get, "https://test.example.com")
+          MSG
+        )
+      end
+    end
+  end
+
+  it "contains registered stubs on failure (with headers)" do
+    WebMock.wrap do
+      WebMock.stub(:post, "https://test.example.com").with(headers: {"Content-Type" => "application/json"})
+      begin
+        HTTP::Client.get("https://www.example.com/")
+      rescue ex : WebMock::NetConnectNotAllowedError
+        ex.message.not_nil!.strip.should eq(
+          <<-MSG
+          Real HTTP connections are disabled. Unregistered request: GET https://www.example.com/ with headers {"Connection" => "close", "Host" => "www.example.com"}
+
+          You can stub this request with the following snippet:
+
+          WebMock.stub(:get, "https://www.example.com/").
+            to_return(body: "")
+
+          Registered request stubs:
+
+          stub(:post, "https://test.example.com").
+            with(
+              headers: {
+                "Content-Type" => "application/json"
+              }
+            )
+          )
+          MSG
+        )
+      end
+    end
+  end
+
+  it "contains registered stubs on failure (with body)" do
+    WebMock.wrap do
+      WebMock.stub(:post, "https://test.example.com").with(body: "line1\nline2")
+      begin
+        HTTP::Client.get("https://www.example.com/")
+      rescue ex : WebMock::NetConnectNotAllowedError
+        ex.message.not_nil!.strip.should eq(
+          <<-MSG
+          Real HTTP connections are disabled. Unregistered request: GET https://www.example.com/ with headers {"Connection" => "close", "Host" => "www.example.com"}
+
+          You can stub this request with the following snippet:
+
+          WebMock.stub(:get, "https://www.example.com/").
+            to_return(body: "")
+
+          Registered request stubs:
+
+          stub(:post, "https://test.example.com").
+            with(
+              body: "line1\\nline2"
+            )
+          )
+          MSG
+        )
+      end
+    end
+  end
+
+  it "contains registered stubs on failure (with headers and body)" do
+    WebMock.wrap do
+      WebMock.stub(:post, "https://test.example.com").with(body: "line1\nline2", headers: {"Content-Type" => "application/json", "Accept" => "*/*"})
+      begin
+        HTTP::Client.get("https://www.example.com/")
+      rescue ex : WebMock::NetConnectNotAllowedError
+        ex.message.not_nil!.strip.should eq(
+          <<-MSG
+          Real HTTP connections are disabled. Unregistered request: GET https://www.example.com/ with headers {"Connection" => "close", "Host" => "www.example.com"}
+
+          You can stub this request with the following snippet:
+
+          WebMock.stub(:get, "https://www.example.com/").
+            to_return(body: "")
+
+          Registered request stubs:
+
+          stub(:post, "https://test.example.com").
+            with(
+              body: "line1\\nline2",
+              headers: {
+                "Content-Type" => "application/json",
+                "Accept" => "*/*"
+              }
+            )
+          )
+          MSG
+        )
+      end
+    end
+  end
+
   it "works with request callbacks" do
     WebMock.wrap do
       WebMock.stub(:get, "http://www.example.com").with(query: {"foo" => "bar"})
@@ -388,7 +502,7 @@ describe WebMock do
   end
 
   # Commented so that specs run fast, but uncomment to try it (it works)
-  #it "calls callback after live request" do
+  # it "calls callback after live request" do
   #  WebMock.wrap do
   #    WebMock.callbacks.add do
   #      after_live_request do |request, response|
@@ -398,15 +512,15 @@ describe WebMock do
   #    WebMock.allow_net_connect = true
   #    HTTP::Client.get("http://www.example.net")
   #  end
-  #end
+  # end
 
-  #it "doesn't error if callback is not set" do
+  # it "doesn't error if callback is not set" do
   #  WebMock.wrap do
   #    WebMock.allow_net_connect = true
   #    client = HTTP::Client.get("http://www.example.net")
   #    client.status_code.should eq 200
   #  end
-  #end
+  # end
 
   # it "allows net connect" do
   #   WebMock.wrap do
diff --git a/src/webmock.cr b/src/webmock.cr
index ce5210d..411a56e 100644
--- a/src/webmock.cr
+++ b/src/webmock.cr
@@ -33,6 +33,10 @@ module WebMock
     @@registry.find_stub(request)
   end
 
+  def stubs
+    @@registry.stubs
+  end
+
   def callbacks
     @@callbacks
   end
diff --git a/src/webmock/net_connect_not_allowed_error.cr b/src/webmock/net_connect_not_allowed_error.cr
index 5e2a751..9f01de2 100644
--- a/src/webmock/net_connect_not_allowed_error.cr
+++ b/src/webmock/net_connect_not_allowed_error.cr
@@ -13,6 +13,7 @@ class WebMock::NetConnectNotAllowedError < Exception
       io << "\n\n"
       stubbing_instructions(request, io)
       io << "\n\n"
+      registered_requests(io)
     end
   end
 
@@ -61,6 +62,14 @@ class WebMock::NetConnectNotAllowedError < Exception
     io << %[  to_return(body: "")]
   end
 
+  private def registered_requests(io)
+    return if WebMock.stubs.empty?
+    io << "Registered request stubs:"
+    io << "\n\n"
+    WebMock.stubs.each { |stub| io << StubSnippet.new(stub).to_s }
+    io << "\n\n"
+  end
+
   private def request_uri_to_s(request, io)
     io << request.scheme
     io << "://"
diff --git a/src/webmock/stub.cr b/src/webmock/stub.cr
index f40d869..f34b6be 100644
--- a/src/webmock/stub.cr
+++ b/src/webmock/stub.cr
@@ -1,4 +1,6 @@
 class WebMock::Stub
+  getter :method, :uri, :expected_headers, :expected_body, :expected_query
+
   @method : String
   @uri : URI
   @expected_headers : HTTP::Headers?
diff --git a/src/webmock/stub_registry.cr b/src/webmock/stub_registry.cr
index 789660c..503f38e 100644
--- a/src/webmock/stub_registry.cr
+++ b/src/webmock/stub_registry.cr
@@ -1,4 +1,6 @@
 struct WebMock::StubRegistry
+  getter :stubs
+
   def initialize
     @stubs = [] of Stub
   end
diff --git a/src/webmock/stub_snippet.cr b/src/webmock/stub_snippet.cr
new file mode 100644
index 0000000..093f001
--- /dev/null
+++ b/src/webmock/stub_snippet.cr
@@ -0,0 +1,35 @@
+struct WebMock::StubSnippet
+  def initialize(stub : Stub)
+    @stub = stub
+  end
+
+  def to_s
+    String.build do |io|
+      io << "stub(:#{@stub.method.downcase}, \"#{@stub.uri}\""
+      if body || headers
+        io << ").\n  with(\n"
+        if body
+          io << "    body: \"#{body.to_s.gsub("\n", "\\n")}\""
+          io << ",\n" if headers
+        end
+        if headers
+          io << "    headers: {\n      "
+          io << headers.not_nil!.map { |key, values| "\"#{key}\" => \"#{values.join(", ")}\"" }.join(",\n      ")
+          io << "\n    }\n"
+        else
+          io << "\n"
+        end
+        io << "  )\n"
+      end
+      io << ")\n"
+    end
+  end
+
+  private def body
+    @stub.expected_body
+  end
+
+  private def headers
+    @stub.expected_headers
+  end
+end