Refresh Tokens & Scopes
Learn about refresh tokens for obtaining new access tokens without re-authentication and the role of scopes in defining access permissions.
Refresh Tokens & Scopes is a free OAuth2 & OpenID Connect Deep Dive lesson on CoddyKit — lesson 2 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the OAuth2 & OpenID Connect Deep Dive learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Keep Your Apps Authorized
Imagine using an app that needs to access your online photos. It gets permission, but what if that permission expires after just an hour?
You'd have to log in again and grant permission every single time! That's not a great user experience, is it?
The Short Life of Access Tokens
Access tokens are like temporary keys. They grant access to specific resources (like your photos) for a short time, often minutes or hours.
This short lifespan is a crucial security feature. If an access token is stolen, an attacker has a limited window to use it, reducing potential damage.
Introducing Refresh Tokens
To solve the constant re-login problem, OAuth2 uses refresh tokens. Think of them as a special, long-term key.
An application uses a refresh token to quietly request a brand new access token from the Authorization Server without needing you to re-enter your credentials.
The Refresh Process
When your access token expires, the client application sends its refresh token to the Authorization Server. This happens in the background.
If the refresh token is valid, the server issues a new access token (and sometimes a new refresh token too!). Your app continues working seamlessly.
public class RefreshExample {
public static void main(String[] args) {
System.out.println("1. Access token expires.");
System.out.println("2. Client sends refresh token.");
System.out.println("3. Authorization Server validates.");
System.out.println("4. New access token issued.");
System.out.println("5. App continues without re-login.");
}
}Protecting Refresh Tokens
Since refresh tokens can grant new access tokens, they are very powerful and must be protected carefully. They are more sensitive than access tokens.
- Store securely: Encrypt them or keep them in secure, HTTP-only cookies.
- Revoke: If compromised, they must be immediately revoked by the user or server.
- Limited use: Some systems issue new refresh tokens with each refresh, invalidating the old one.
What Are Scopes?
Now let's talk about scopes. Scopes are simple strings that define the exact permissions an application is requesting from you.
They control *what* an application can do with your resources once it has an access token. Think of them as permission labels, like 'read_email' or 'write_photos'.
How Scopes are Applied
When an app asks for your permission (during the authorization step), it will explicitly list the scopes it needs.
You, the resource owner, then decide which of those permissions to grant. For example, you might grant 'read_profile' but deny 'write_posts'.
Practical Scope Examples
Scopes are typically defined by the Resource Server, and their names can vary. Here are some common examples you might encounter:
openid: Requesting basic identity info (often used in OpenID Connect).profile: Access to your basic profile data (name, picture, etc.).email: Access to your primary email address.https://www.googleapis.com/auth/photos.readonly: Read-only access to Google Photos.
Scopes Persist on Refresh
When an application uses a refresh token to get a new access token, the new access token will generally carry the same scopes that were originally granted.
The application can't magically gain new permissions during a refresh; it must request them again through a full user authorization flow if it needs more access.
Quick Check: Tokens & Scopes
Which of the following statements about Refresh Tokens and Scopes are TRUE?
Summary: Refresh & Scopes
We've covered two vital OAuth2 concepts that enhance both security and user experience:
- Refresh Tokens: Long-lived credentials used to obtain new, short-lived access tokens without user interaction, improving UX.
- Scopes: Granular permissions that define what an application is authorized to do on a user's behalf.
Understanding these helps you build more secure and user-friendly applications!
Frequently asked questions
Is the “Refresh Tokens & Scopes” lesson free?
Yes — the full text of “Refresh Tokens & Scopes” is free to read here on the web, and the OAuth2 & OpenID Connect Deep Dive course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the OAuth2 & OpenID Connect Deep Dive course, upgrade to CoddyKit PRO.
What will I learn in “Refresh Tokens & Scopes”?
Learn about refresh tokens for obtaining new access tokens without re-authentication and the role of scopes in defining access permissions. You practise OAuth2 & OpenID Connect Deep Dive with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start OAuth2 & OpenID Connect Deep Dive?
No prior experience is required. OAuth2 & OpenID Connect Deep Dive on CoddyKit is structured for beginners through advanced learners; this is — lesson 2 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “Refresh Tokens & Scopes” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this OAuth2 & OpenID Connect Deep Dive lesson?
Yes. Every OAuth2 & OpenID Connect Deep Dive lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- PKCE for Public Clients
- Refresh Tokens & Scopes
- Resource Owner Password Credentials
- Token Exchange (RFC 8693)