diff --git a/internal/domain/config.go b/internal/domain/config.go
new file mode 100644
index 0000000..e3d30c0
--- /dev/null
+++ b/internal/domain/config.go
@@ -0,0 +1,23 @@
+package domain
+
+import (
+	"testing"
+
+	"github.com/spf13/viper"
+)
+
+// TODO(toby3d): create Config domain
+
+// TestConfig returns a valid *viper.Viper with the generated test data filled in.
+func TestConfig(tb testing.TB) *viper.Viper {
+	tb.Helper()
+
+	v := viper.New()
+	v.Set("indieauth.jwtSecret", "hackme")
+	v.Set("indieauth.jwtSigningAlgorithm", "HS256")
+	v.Set("server.domain", "example.com")
+	v.Set("server.protocol", "https")
+	v.Set("server.rootUrl", "{{protocol}}://{{domain}}/")
+
+	return v
+}