diff --git a/api/app.js b/api/echo.js
similarity index 100%
rename from api/app.js
rename to api/echo.js
diff --git a/index.js b/index.js
index 668bd02..307a09e 100644
--- a/index.js
+++ b/index.js
@@ -29,6 +29,8 @@ app.use(express.urlencoded({ extended: false }));
 app.use(express.raw({ type: "*/*" }));
 app.set("json spaces", 2);
 app.all("/basic-auth", passport.authenticate("basic", { session: false }));
-app.all("/*", require("./api/app.js"));
+app.all("/*", require("./api/echo.js"));
 
-app.listen(process.env.PORT || 8080);
+if (require.main === module) app.listen(process.env.PORT || 8080);
+
+module.exports = app;
diff --git a/vercel.json b/vercel.json
index 0eefc00..575dce4 100644
--- a/vercel.json
+++ b/vercel.json
@@ -1,4 +1,4 @@
 {
   "version": 2,
-  "routes": [{ "src": "/.*", "dest": "/api/app.js" }]
+  "routes": [{ "src": "/.*", "dest": "/api/echo.js" }]
 }