diff --git a/typings/global.d.ts b/typings/global.d.ts
index c79b31c..22db89b 100644
--- a/typings/global.d.ts
+++ b/typings/global.d.ts
@@ -2,6 +2,7 @@
 declare namespace NodeJS {
   interface ProcessEnv {
     readonly NODE_ENV: 'development' | 'production'
+    readonly PORT: string
   }
 }