diff --git a/src/state/lobby/event.go b/src/state/lobby/event.go
new file mode 100644
index 0000000..ae094a4
--- /dev/null
+++ b/src/state/lobby/event.go
@@ -0,0 +1,17 @@
+package lobby
+
+type Event interface {
+	LobbyEvent()
+}
+
+type PlayerJoin struct {
+	ID int
+}
+
+func (PlayerJoin) LobbyEvent() {}
+
+type PlayerLeave struct {
+	ID int
+}
+
+func (PlayerLeave) LobbyEvent() {}
diff --git a/src/state/lobby/storage.go b/src/state/lobby/storage.go
new file mode 100644
index 0000000..3e6634d
--- /dev/null
+++ b/src/state/lobby/storage.go
@@ -0,0 +1,16 @@
+package lobby
+
+import (
+	"context"
+	"io"
+)
+
+type Storage interface {
+	PlayerIDs(context.Context) ([]int, error)
+}
+
+type DB struct{}
+
+func (db DB) PlayerIDs(ctx context.Context) ([]int, error) {
+	return nil, io.EOF
+}