diff --git a/.eslintrc b/.eslintrc
index 5d21a014..16fb3b5c 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -10,6 +10,9 @@
     "jest": true,
     "mocha": true
   },
+  "parserOptions": {
+    "sourceType": "module"
+  },
   "globals": {
     "SELECT": true,
     "INSERT": true,
diff --git a/bookshop/db/init.js b/bookshop/db/init.js
index 1dec13c3..fb7c3f9f 100644
--- a/bookshop/db/init.js
+++ b/bookshop/db/init.js
@@ -6,7 +6,7 @@
 
 // NOTE: We use cds.on('served') to delay the UPSERTs after the db init
 // to run after all INSERTs from .csv files happened.
-module.exports = cds.on('served', ()=> cds.run(
+cds.on('served', ()=> cds.run(
   UPSERT.into ('sap.common.Currencies') .columns (
     [ 'code', 'symbol', 'name' ]
   ) .rows (
diff --git a/bookshop/index.js b/bookshop/index.js
index 7bffbe36..6c6f39b9 100644
--- a/bookshop/index.js
+++ b/bookshop/index.js
@@ -1,2 +1 @@
-const { CatalogService } = require('./srv/cat-service')
-module.exports = { CatalogService }
+export { CatalogService } from './srv/cat-service'
diff --git a/bookshop/jsconfig.json b/bookshop/jsconfig.json
new file mode 100644
index 00000000..b7374dc7
--- /dev/null
+++ b/bookshop/jsconfig.json
@@ -0,0 +1,11 @@
+{
+  "compilerOptions": {
+    "module": "NodeNext",
+    "moduleResolution": "nodenext",
+    "paths": {
+      "#cds/*": [
+        "./@cds/*"
+      ]
+    }
+  }
+}
diff --git a/bookshop/package.json b/bookshop/package.json
index 6c24d667..632f3ecc 100644
--- a/bookshop/package.json
+++ b/bookshop/package.json
@@ -2,6 +2,7 @@
   "name": "@capire/bookshop",
   "version": "1.0.0",
   "description": "A simple self-contained bookshop service.",
+  "type": "module",
   "files": [
     "app",
     "srv",
@@ -10,7 +11,8 @@
     "index.js"
   ],
   "devDependencies": {
-    "@cap-js/sqlite": "*"
+    "@cap-js/sqlite": "*",
+    "@cap-js/cds-typer": ">=0.1"
   },
   "dependencies": {
     "@sap/cds": "^7",
@@ -21,5 +23,8 @@
     "genres": "cds serve test/genres.cds",
     "start": "cds-serve",
     "watch": "cds watch"
+  },
+  "imports": {
+    "#cds/*": "./@cds/*/index.js"
   }
 }
diff --git a/bookshop/srv/admin-service.js b/bookshop/srv/admin-service.js
index d737a65a..d6059488 100644
--- a/bookshop/srv/admin-service.js
+++ b/bookshop/srv/admin-service.js
@@ -1,6 +1,6 @@
-const cds = require('@sap/cds/lib')
+import cds from '@sap/cds'
 
-module.exports = class AdminService extends cds.ApplicationService { init(){
+export class AdminService extends cds.ApplicationService { init(){
   this.before ('NEW','Authors', genid)
   this.before ('NEW','Books', genid)
   return super.init()
diff --git a/bookshop/srv/cat-service.js b/bookshop/srv/cat-service.js
index 3c557078..2be1cec4 100644
--- a/bookshop/srv/cat-service.js
+++ b/bookshop/srv/cat-service.js
@@ -1,29 +1,36 @@
-const cds = require('@sap/cds')
+import cds from '@sap/cds'
 
-class CatalogService extends cds.ApplicationService { init(){
+export class CatalogService extends cds.ApplicationService { init() {
 
-  const { Books } = cds.entities ('sap.capire.bookshop')
+  const { Books } = cds.entities('sap.capire.bookshop')
   const { ListOfBooks } = this.entities
 
-  // Reduce stock of ordered books if available stock suffices
-  this.on ('submitOrder', async req => {
-    const {book,quantity} = req.data
-    if (quantity < 1) return req.reject (400,`quantity has to be 1 or more`)
-    let b = await SELECT `stock` .from (Books,book)
-    if (!b) return req.error (404,`Book #${book} doesn't exist`)
-    let {stock} = b
-    if (quantity > stock) return req.reject (409,`${quantity} exceeds stock for book #${book}`)
-    await UPDATE (Books,book) .with ({ stock: stock -= quantity })
-    await this.emit ('OrderedBook', { book, quantity, buyer:req.user.id })
-    return { stock }
-  })
-
   // Add some discount for overstocked books
-  this.after ('READ', ListOfBooks, each => {
+  this.after('READ', ListOfBooks, each => {
     if (each.stock > 111) each.title += ` -- 11% discount!`
   })
 
+  // Reduce stock of ordered books if available stock suffices
+  this.on('submitOrder', async req => {
+    let { book:id, quantity } = req.data
+    let book = await SELECT.from (Books, id, b => b.stock)
+
+    // Validate input data
+    if (!book) return req.error (404, `Book #${id} doesn't exist`)
+    if (quantity < 1) return req.error (400, `quantity has to be 1 or more`)
+    if (quantity > book.stock) return req.error (409, `${quantity} exceeds stock for book #${id}`)
+
+    // Reduce stock in database and return updated stock value
+    await UPDATE (Books, id) .with ({ stock: book.stock -= quantity })
+    return book
+  })
+
+  // Emit event when an order has been submitted
+  this.after('submitOrder', async (_,req) => {
+    let { book, quantity } = req.data
+    await this.emit('OrderedBook', { book, quantity, buyer: req.user.id })
+  })
+
+  // Delegate requests to the underlying generic service
   return super.init()
 }}
-
-module.exports = { CatalogService }
diff --git a/bookshop/srv/user-service.js b/bookshop/srv/user-service.js
index 2ecb68d9..446dbf23 100644
--- a/bookshop/srv/user-service.js
+++ b/bookshop/srv/user-service.js
@@ -1,5 +1,5 @@
-const cds = require('@sap/cds')
-module.exports = class UserService extends cds.Service { init(){
+import cds from '@sap/cds'
+export class UserService extends cds.Service { init(){
   this.on('READ', 'me', ({ tenant, user, locale }) => ({ id: user.id, locale, tenant }))
   this.on('login', (req) => {
     if (req.user._is_anonymous)