Why you shouldn’t use access tokens in your front-end any more

And how to move authentication to the server-side

To obtain authorization for API-endpoints, many Single-Page Applications use OAuth2. Word has it, lately, you should not use access_tokens in the front-end any more. Why is that?

Read this article to learn:

• How a Single Page Application obtains authorization at the client-side
• How this may be a risk
• What the alternative is

How modern web applications authenticate

Modern web applications authenticate users with Single Sign-On. Medium is a good example of this: You can log-in with your Google account, at Spotify you can log in with Facebook, and so forth.

This means the log-in page is not part of a modern web application anymore. This has some implications:

• When you log-in, you are logged into Google, for example. When you log in with Google, they issue some sort of token which represents your session at Google.
• When you want to log-in at, say Medium, you will have to leave Medium.com, navigate to Google to authenticate, and then navigate back to Medium.com.

This is schematically displayed in the following diagram: