diff --git a/model/util.ts b/model/util.ts
new file mode 100644
index 0000000..630b358
--- /dev/null
+++ b/model/util.ts
@@ -0,0 +1,22 @@
+import { Session as ISession } from 'express-session';
+
+export interface PromiseExecutor<T> {
+  resolve: (value: T) => void;
+  reject: (reason?: any) => void;
+}
+
+export interface LookupResolveValue {
+  address: string;
+  name: string;
+  state: number;
+}
+
+export interface Lookup extends PromiseExecutor<LookupResolveValue> {
+  name?: string;
+  address?: string;
+}
+
+export interface Session extends ISession {
+  socketId: string;
+  conversation: any;
+}