Letting other things talk to your app

Every real app eventually needs to talk to the outside world in both directions. Up to this point in the course, we've focused on your app talking out to other services. This lesson covers the other direction — letting external things talk in to your app through webhooks and APIs.

In an agent-driven world, this matters more than it used to. If you want an AI agent to interact with the things you build — read data, create records, take action — your app has to expose a way for it to do that. We'll cover the two main patterns, explain when each one applies, and close with the security basics you should never skip.

• The difference between webhooks (things calling in to tell you something) and APIs (things calling in to do something)
• Why this matters especially in a world where AI agents need to interact with your app
• How the bookmarks app in Course 3 uses both patterns in practice
• Why API tokens are the non-negotiable way to authenticate incoming requests