Authentication vs Authorization

Source: Dev.to

Authentication

Authentication is about confirming a user’s identity. It is the process the system uses to verify that you are who you claim to be.

A common example is logging into an application. When you enter your email and password, the system checks whether those credentials match what it has stored. If they do, you are authenticated.

Common authentication methods

• Passwords
• One‑time codes (OTP)
• Biometrics (fingerprints, facial recognition)
• Signing in with providers such as Google or GitHub

At the end of the process, the system knows who the user is.

Authorization

Authorization happens after authentication. Once the system knows who the user is, it determines what that user is allowed to do.

Example: admin dashboard

• Regular users can view their own data
• Moderators can edit content
• Administrators can manage users

Even though all of them are authenticated, they have different permissions. Authorization controls those access levels.

Typical scenario

• Alice logs in → authentication
• The system checks if Alice is an admin → authorization

Authentication answers the question: “Is this person really Alice?”
Authorization answers the question: “What is Alice allowed to do?”

Why the Difference Matters

Separating authentication and authorization makes systems more secure and easier to manage. It allows developers to:

• Verify user identities
• Control access to specific features
• Implement role‑based permissions
• Protect sensitive data

Most modern applications rely on both processes working together. While authentication verifies who the user is, authorization determines what the user can do. Understanding this distinction is an important step when building secure and scalable applications.