diff --git a/ui/attribute_normalization_test.go b/ui/attribute_normalization_test.go
new file mode 100644
index 00000000..c29cc55e
--- /dev/null
+++ b/ui/attribute_normalization_test.go
@@ -0,0 +1,76 @@
+//go:build !js || !wasm
+
+package ui_test
+
+import (
+	"testing"
+
+	"github.com/monstercameron/GoWebComponents/html"
+	"github.com/monstercameron/GoWebComponents/ui"
+)
+
+func rawDiv(parseRaw map[string]any) string {
+	parseOut, _ := ui.RenderToString(html.Tag("div", html.Props{Raw: parseRaw}, ui.Text("x")))
+	return parseOut
+}
+
+// Deepens the ReactDOMServerIntegrationAttributes port toward equivalency: the
+// React-prop -> HTML-attribute name normalizations and the props that must never
+// be emitted as attributes.
+func TestAttributeNameNormalization(t *testing.T) {
+	if parseGot := rawDiv(map[string]any{"className": "c1"}); parseGot != `<div class="c1">x</div>` {
+		t.Errorf("className->class: %q", parseGot)
+	}
+	parseLabel, _ := ui.RenderToString(html.Tag("label", html.Props{Raw: map[string]any{"htmlFor": "id1"}}, ui.Text("x")))
+	if parseLabel != `<label for="id1">x</label>` {
+		t.Errorf("htmlFor->for: %q", parseLabel)
+	}
+}
+
+// Internal/framework props are never serialized as attributes (React: ref, key,
+// children, dangerouslySetInnerHTML, suppress*Warning; GWC: key, children, event
+// handlers, the DOM-ref sink).
+func TestNonAttributePropsAreNotEmitted(t *testing.T) {
+	cases := []struct {
+		name string
+		raw  map[string]any
+	}{
+		{"key", map[string]any{"key": "k", "id": "real"}},
+		{"children", map[string]any{"children": "nope", "id": "real"}},
+		{"onClick", map[string]any{"onClick": func() {}, "id": "real"}},
+		{"onclick-lower", map[string]any{"onclick": func() {}, "id": "real"}},
+	}
+	for _, parseCase := range cases {
+		if parseGot := rawDiv(parseCase.raw); parseGot != `<div id="real">x</div>` {
+			t.Errorf("%s should be omitted: %q", parseCase.name, parseGot)
+		}
+	}
+}
+
+// Style maps serialize to a deterministic, sorted "k:v;k:v" string (React sorts
+// for stable SSR output).
+func TestStyleMapSerialization(t *testing.T) {
+	parseOut, _ := ui.RenderToString(html.Div(html.Props{
+		Style: map[string]string{"margin": "0", "color": "red", "z-index": "2"},
+	}, ui.Text("x")))
+	if parseOut != `<div style="color:red;margin:0;z-index:2">x</div>` {
+		t.Errorf("style map = %q, want sorted color;margin;z-index", parseOut)
+	}
+}
+
+// Numeric and boolean attribute values (via Raw): a number stringifies, a true
+// boolean is a bare attribute, a false boolean is omitted.
+func TestNumericAndBooleanAttributeValues(t *testing.T) {
+	if parseGot := rawDiv(map[string]any{"tabindex": 0}); parseGot != `<div tabindex="0">x</div>` {
+		t.Errorf("numeric zero: %q", parseGot)
+	}
+	if parseGot := rawDiv(map[string]any{"data-n": 42}); parseGot != `<div data-n="42">x</div>` {
+		t.Errorf("numeric: %q", parseGot)
+	}
+	if parseGot := rawDiv(map[string]any{"hidden": true}); parseGot != `<div hidden>x</div>` {
+		t.Errorf("bool true: %q", parseGot)
+	}
+	if parseGot := rawDiv(map[string]any{"hidden": false}); parseGot != `<div>x</div>` {
+		t.Errorf("bool false should be omitted: %q", parseGot)
+	}
+}