diff --git a/internal/config.go b/internal/config.go
new file mode 100644
index 0000000..e7f8312
--- /dev/null
+++ b/internal/config.go
@@ -0,0 +1,11 @@
+package internal
+
+// Config holds the service's runtime configuration.
+type Config struct {
+	Addr string
+}
+
+// DefaultConfig returns the default runtime configuration.
+func DefaultConfig() Config {
+	return Config{Addr: ":8080"}
+}