diff --git a/lib/rspamd-ruby.rb b/lib/rspamd-ruby.rb
index 7787779..5ef5c45 100644
--- a/lib/rspamd-ruby.rb
+++ b/lib/rspamd-ruby.rb
@@ -7,7 +7,7 @@
 module Rspamd
   class << self
     def setup(config)
-      @config = config.deep_symbolize_keys
+      @config = config&.deep_symbolize_keys
       @clients = {}
     end
 
diff --git a/test/setup_test.rb b/test/setup_test.rb
index a47ec44..089b50b 100644
--- a/test/setup_test.rb
+++ b/test/setup_test.rb
@@ -27,6 +27,13 @@ def test_caches_client_instances
     assert_same client1, client2
   end
 
+  def test_returns_stub_when_config_is_nil
+    Rspamd.setup(nil)
+
+    client = Rspamd.client_for(:outbound)
+    assert_instance_of Rspamd::ClientStub, client
+  end
+
   def test_returns_stub_when_not_configured
     client = Rspamd.client_for(:outbound)
     assert_instance_of Rspamd::ClientStub, client