diff --git a/examples/subscription/memory.js b/examples/subscription/memory.js
new file mode 100644
index 00000000..754e543c
--- /dev/null
+++ b/examples/subscription/memory.js
@@ -0,0 +1,84 @@
+'use strict'
+
+const mercurius = require('../..')
+const Fastify = require('fastify')
+
+const app = Fastify({ logger: { level: 'debug' } })
+
+// list of products
+const products = []
+
+// graphql schema
+const schema = `
+  type Product {
+    name: String!
+    state: String!
+  }
+
+  type Query {
+    products: [Product]
+  }
+
+  type Mutation {
+    addProduct(name: String!, state: String!): Product
+  }
+
+  type Subscription {
+    productAdded: Product
+  }
+`
+
+// graphql resolvers
+const resolvers = {
+  Query: {
+    products: () => products
+  },
+  Mutation: {
+    addProduct: async (_, { name, state }, { pubsub }) => {
+      const product = { name, state }
+
+      products.push(product)
+
+      pubsub.publish({
+        topic: 'new_product_updates',
+        payload: {
+          productAdded: product
+        }
+      })
+
+      return product
+    }
+  },
+  Subscription: {
+    productAdded: {
+      subscribe: async (_, __, { pubsub }) => {
+        return await pubsub.subscribe('new_product_updates')
+      }
+    }
+  }
+}
+
+// server start
+const start = async () => {
+  try {
+    // register GraphQl
+    app.register(mercurius, {
+      schema,
+      resolvers,
+      graphiql: true,
+      subscription: {
+        async onConnect ({ payload }) {
+          app.log.info({ payload }, 'connection_init data')
+          return true
+        }
+      }
+    })
+
+    // start server
+    await app.listen({ port: 3000 })
+  } catch (error) {
+    app.log.error(error)
+  }
+}
+
+start()
diff --git a/static/main.js b/static/main.js
index 485d39e8..080ee29e 100644
--- a/static/main.js
+++ b/static/main.js
@@ -42,7 +42,7 @@ function render () {
 
 function importDependencies () {
   const link = document.createElement('link')
-  link.href = 'https://unpkg.com/graphiql@2.0.2/graphiql.min.css'
+  link.href = 'https://unpkg.com/graphiql@2.0.9/graphiql.min.css'
   link.type = 'text/css'
   link.rel = 'stylesheet'
   link.media = 'screen,print'
@@ -52,7 +52,7 @@ function importDependencies () {
   return importer.urls([
     'https://unpkg.com/react@18.2.0/umd/react.production.min.js',
     'https://unpkg.com/react-dom@18.2.0/umd/react-dom.production.min.js',
-    'https://unpkg.com/graphiql@2.0.2/graphiql.min.js'
+    'https://unpkg.com/graphiql@2.0.9/graphiql.min.js'
   ])
 }
 
diff --git a/static/sw.js b/static/sw.js
index 2c9f3ca5..ef32ba49 100644
--- a/static/sw.js
+++ b/static/sw.js
@@ -2,13 +2,13 @@
 
 self.addEventListener('install', function (e) {
   e.waitUntil(
-    caches.open('graphiql-v2.0.2').then(function (cache) {
+    caches.open('graphiql-v2.0.9').then(function (cache) {
       return cache.addAll([
         './main.js',
-        'https://unpkg.com/graphiql@2.0.2/graphiql.css',
+        'https://unpkg.com/graphiql@2.0.9/graphiql.css',
         'https://unpkg.com/react@18.2.0/umd/react.production.min.js',
         'https://unpkg.com/react-dom@18.2.0/umd/react-dom.production.min.js',
-        'https://unpkg.com/graphiql@2.0.2/graphiql.min.js'
+        'https://unpkg.com/graphiql@2.0.9/graphiql.min.js'
       ])
     })
   )