Types of authentication > By type of app
When you start learning about Dialogflow's REST API, pretty much all the documentation usually points to this page, which is titled, using [unintelligible 00:00:10] to access Google APIs. It's considered to be like the starting point for you to work with the REST API. In fact, most of the documentation that you see will make an assumption that you have actually gone through this- I guess you can say this one page document you have here, this web page, before you move onto the other steps in your integration.
As it happens, you might be tempted to skip what looks like sort of a theoretical introduction to the authentication system. You shouldn't do that, because this part is quite important. I'm just going to go over whatever is already on the page for now, and then we'll take a look into each of these in future videos. The first thing you see is that they're talking about five scenarios. They're talking about five scenarios in which you can use the REST API. The first one is for web server applications. These are the cases where you have a website which is going to let people log into their Dialogflow account.
You might have seen similar apps, for example, if you were to use some online service, which lets you save your file to your Google Drive account, you will first have to authenticate with your Google Drive account and you have to say, "Yes. I give permission to this app to access my Google Drive," before you're actually allowed to save your file to your Google drive. That's a good example of these web server applications.
Finally, we come to the service accounts. Service accounts are useful for what they call a server to server interactions, where you're going to have some code which is running on behalf of the agent that you have already created in Dialogflow. If that was not very clear, that's okay. We'll be going over this in some detail later on.
The important thing here is that, in the case of the service account, you will have a different kind of process for the authentication. Again, we will be going into some details about that also in a future video. You'll also notice that most of the cases where the Dialogflow-- In most of the documentation for the REST API in Dialogflow, it always talks about the service account. It's not talking about the other kind of scenarios.
That actually makes a lot of sense and you'll see why very soon. With that said, these are the five types of scenarios where you might want to be integrating your Dialogflow agent and where the REST API will be helpful. We will be taking a closer look at these in future videos.