diff --git a/app/graphiql.js b/app/graphiql.js
index d320482d..23e4a770 100644
--- a/app/graphiql.js
+++ b/app/graphiql.js
@@ -1,10 +1,14 @@
 const path = require('path')
+const express = require('express')
+const router = express.Router()
 
-module.exports = (req, res, next) => {
+router.get('/', (req, res, next) => {
   if (req.query.query) {
     // Forward GET requests with query URL parameter to GraphQL server
     next()
   } else {
     res.sendFile(path.join(__dirname, 'graphiql.html'))
   }
-}
+})
+
+module.exports = router
diff --git a/index.js b/index.js
index d90aad43..dbdd878d 100644
--- a/index.js
+++ b/index.js
@@ -3,7 +3,7 @@ const DEBUG = cds.debug('adapters')
 const GraphQLAdapter = require('./lib/GraphQLAdapter')
 
 let services
-const _collectServicesAndMountAdapter = (srv, options) => {
+const collectServicesAndMountAdapter = (srv, options) => {
   if (!services) {
     services = {}
     cds.on('served', () => {
@@ -15,4 +15,4 @@ const _collectServicesAndMountAdapter = (srv, options) => {
   services[srv.name] = srv
 }
 
-module.exports = _collectServicesAndMountAdapter
+module.exports = collectServicesAndMountAdapter
diff --git a/lib/GraphQLAdapter.js b/lib/GraphQLAdapter.js
index 6dc63f4e..ed73877a 100644
--- a/lib/GraphQLAdapter.js
+++ b/lib/GraphQLAdapter.js
@@ -20,7 +20,7 @@ function GraphQLAdapter(options) {
       next()
     })
 
-  if (options.graphiql) router.get('/', graphiql)
+  if (options.graphiql) router.use(graphiql)
   router.use((req, res) => createHandler({ schema, context: { req, res }, ...options })(req, res))
   return router
 }