diff --git a/index.js b/index.js
index d084afa84b..19d020f11f 100644
--- a/index.js
+++ b/index.js
@@ -18,6 +18,14 @@ const server = app.listen(port, () => {
   console.log(`Listening on ${port}`)
 })
 
+// The number of seconds an idle Keep-Alive connection is kept open. This should be greater than the Heroku Router's
+// Keep-Alive idle timeout of 90 seconds:
+// - to ensure that the closing of idle connections is always initiated by the router and not the Node.js server
+// - to prevent a race condition if the router sends a request to the app just as Node.js is closing the connection
+// https://devcenter.heroku.com/articles/http-routing#keepalives
+// https://nodejs.org/api/http.html#serverkeepalivetimeout
+server.keepAliveTimeout = 95 * 1000
+
 process.on('SIGTERM', async () => {
   console.log('SIGTERM signal received: gracefully shutting down')
   if (server) {