diff --git a/twitch/eventsub/stream.go b/twitch/eventsub/stream.go
new file mode 100644
index 0000000..55a9775
--- /dev/null
+++ b/twitch/eventsub/stream.go
@@ -0,0 +1,18 @@
+package eventsub
+
+// StreamOnline is the payload for a stream.online or stream.offline notification.
+type Stream struct {
+	// ID is the stream ID.
+	// Only present in stream.online messages.
+	ID string `json:"id"`
+	// Broadcaster is the broadcaster's user ID.
+	Broadcaster string `json:"broadcaster_user_id"`
+	// BroadcasterLogin is the broadcaster's user login.
+	BroadcasterLogin string `json:"broadcaster_user_login"`
+	// BoradcasterName is the broadcaster's display name.
+	BroadcasterName string `json:"broadcaster_user_name"`
+	// Type is the stream type, usually "live".
+	Type string `json:"type"`
+	// Started is the time at which the stream started in RFC3339Nano format.
+	Started string `json:"started_at"`
+}
diff --git a/twitch/eventsub/stream_test.go b/twitch/eventsub/stream_test.go
new file mode 100644
index 0000000..edad2b0
--- /dev/null
+++ b/twitch/eventsub/stream_test.go
@@ -0,0 +1,45 @@
+package eventsub_test
+
+import (
+	"testing"
+
+	"github.com/go-json-experiment/json"
+	"github.com/google/go-cmp/cmp"
+	"github.com/zephyrtronium/robot/twitch/eventsub"
+)
+
+func TestStream(t *testing.T) {
+	t.Run("online", func(t *testing.T) {
+		evt := Testdata("stream.online.json")
+		var got eventsub.Stream
+		if err := json.Unmarshal([]byte(evt.Event), &got); err != nil {
+			t.Errorf("couldn't unmarshal payload as stream: %v", err)
+		}
+		want := eventsub.Stream{
+			ID:               "9001",
+			Broadcaster:      "1337",
+			BroadcasterLogin: "cool_user",
+			BroadcasterName:  "Cool_User",
+			Type:             "live",
+			Started:          "2020-10-11T10:11:12.123Z",
+		}
+		if diff := cmp.Diff(want, got); diff != "" {
+			t.Errorf("wrong stream (+got/-want):\n%s", diff)
+		}
+	})
+	t.Run("offline", func(t *testing.T) {
+		evt := Testdata("stream.offline.json")
+		var got eventsub.Stream
+		if err := json.Unmarshal([]byte(evt.Event), &got); err != nil {
+			t.Errorf("couldn't unmarshal payload as stream: %v", err)
+		}
+		want := eventsub.Stream{
+			Broadcaster:      "1337",
+			BroadcasterLogin: "cool_user",
+			BroadcasterName:  "Cool_User",
+		}
+		if diff := cmp.Diff(want, got); diff != "" {
+			t.Errorf("wrong stream (+got/-want):\n%s", diff)
+		}
+	})
+}
diff --git a/twitch/eventsub/testdata/stream.offline.json b/twitch/eventsub/testdata/stream.offline.json
new file mode 100644
index 0000000..bc17c7c
--- /dev/null
+++ b/twitch/eventsub/testdata/stream.offline.json
@@ -0,0 +1,22 @@
+{
+	"subscription": {
+		"id": "f1c2a387-161a-49f9-a165-0f21d7a4e1c4",
+		"type": "stream.offline",
+		"version": "1",
+		"status": "enabled",
+		"cost": 0,
+		"condition": {
+			"broadcaster_user_id": "1337"
+		},
+		"created_at": "2019-11-16T10:11:12.634234626Z",
+		"transport": {
+			"method": "webhook",
+			"callback": "https://example.com/webhooks/callback"
+		}
+	},
+	"event": {
+		"broadcaster_user_id": "1337",
+		"broadcaster_user_login": "cool_user",
+		"broadcaster_user_name": "Cool_User"
+	}
+}
\ No newline at end of file
diff --git a/twitch/eventsub/testdata/stream.online.json b/twitch/eventsub/testdata/stream.online.json
new file mode 100644
index 0000000..55b14a5
--- /dev/null
+++ b/twitch/eventsub/testdata/stream.online.json
@@ -0,0 +1,25 @@
+{
+	"subscription": {
+		"id": "f1c2a387-161a-49f9-a165-0f21d7a4e1c4",
+		"type": "stream.online",
+		"version": "1",
+		"status": "enabled",
+		"cost": 0,
+		"condition": {
+			"broadcaster_user_id": "1337"
+		},
+		"transport": {
+			"method": "webhook",
+			"callback": "https://example.com/webhooks/callback"
+		},
+		"created_at": "2019-11-16T10:11:12.634234626Z"
+	},
+	"event": {
+		"id": "9001",
+		"broadcaster_user_id": "1337",
+		"broadcaster_user_login": "cool_user",
+		"broadcaster_user_name": "Cool_User",
+		"type": "live",
+		"started_at": "2020-10-11T10:11:12.123Z"
+	}
+}
\ No newline at end of file
diff --git a/twitch/eventsub/testdata_test.go b/twitch/eventsub/testdata_test.go
new file mode 100644
index 0000000..13816f0
--- /dev/null
+++ b/twitch/eventsub/testdata_test.go
@@ -0,0 +1,24 @@
+package eventsub_test
+
+import (
+	"embed"
+
+	"github.com/go-json-experiment/json"
+
+	"github.com/zephyrtronium/robot/twitch/eventsub"
+)
+
+//go:embed testdata
+var testdata embed.FS
+
+func Testdata(name string) *eventsub.Event {
+	b, err := testdata.ReadFile("testdata/" + name)
+	if err != nil {
+		panic(err)
+	}
+	var r eventsub.Event
+	if err := json.Unmarshal(b, &r); err != nil {
+		panic(err)
+	}
+	return &r
+}