In this chapter, we added an authentication layer to ensure that only registered users can perform actions on the to-do items. Moreover, thanks to the modest authorization layer, we ensured that users could only access tasks they created. Finally, we showed how simple upload and download capabilities are to implement using a real-world example of bulk imports and exports.
In the next chapter, we will learn how to make our application reliable in production. We will use the tools that Fastify integrates to test our endpoints thoroughly. We want to prevent introducing any disruptions for our users because of lousy code pushed to production.