Comparing OAuth and OpenID: Understanding the Key Differences and Uses


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OAuth and OpenID are two popular authentication protocols that are widely used for authorization and authentication purposes. Both protocols allow users to securely sign in to a website or application without revealing their passwords. However, they have different purposes and uses, and it’s essential to understand the key differences between the two. In this article, we’ll take a closer look at OAuth and OpenID and compare them in detail.

Authorization or Authentication

OAuth (Open Authorization) is an authorization protocol that enables third-party applications to access user data without revealing their passwords. It allows users to grant a limited access to their data stored on one website to another website, without exposing their login credentials. For example, if you use your Google account to sign in to a third-party website, the website is granted access to your basic profile information, but not your Google password.

OpenID, on the other hand, is an authentication protocol that enables users to sign in to multiple websites with a single set of credentials. Instead of creating a new username and password for each website, users can sign in to websites that support OpenID using their existing credentials, such as a Google or Yahoo account. With OpenID, users don’t have to remember multiple usernames and passwords, and they can enjoy a seamless and secure experience while accessing different websites.


One of the main differences between OAuth and OpenID is the purpose they serve. OAuth is mainly used for authorization, while OpenID is used for authentication. OAuth enables users to share their data with third-party applications, while OpenID allows users to sign in to multiple websites with a single set of credentials.

Level of access

Another key difference between the two protocols is the level of access they provide. OAuth provides limited access to user data, while OpenID only provides authentication and doesn’t allow access to user data. OAuth is more secure compared to OpenID because it provides a higher level of control over the data shared with third-party applications.


In terms of implementation, OAuth is more complex compared to OpenID. OAuth involves obtaining an access token, which is then used to access user data. On the other hand, OpenID is straightforward, and users can sign in to websites using their existing credentials.

OpenID Connect and OAuth

OpenID Connect (OIDC) is a protocol that builds on top of OAuth and provides authentication functionality. It is an identity layer on top of the OAuth authorization protocol and enables applications to verify the identity of the end-user.

While OAuth is primarily used for authorization, OpenID Connect provides both authentication and authorization. With OpenID Connect, applications can not only access user data but also verify the identity of the user who is accessing the data.

OpenID Connect also provides additional features compared to OAuth, such as a user info endpoint, which returns information about the authenticated user, and a discovery document, which provides metadata about the OpenID Connect provider. This information can be used to determine the authentication methods supported by the provider and the endpoints used to initiate an authentication flow.

Another key difference between OAuth and OpenID Connect is the way they handle tokens. OAuth provides access tokens that are used to access user data, while OpenID Connect provides identity tokens (also known as ID tokens) that contain information about the authenticated user. ID tokens are JWT (JSON Web Tokens) and include information such as the user’s name, email, and a unique identifier for the user.

In summary, OpenID Connect is an extension of OAuth that provides additional features for authentication and identity management. While OAuth focuses on authorization, OpenID Connect provides a complete solution for authentication and authorization, making it a more comprehensive solution for many use cases.


In conclusion, both OAuth and OpenID serve different purposes, and they are used in different scenarios. OAuth is used for authorization and provides limited access to user data, while OpenID is used for authentication and enables users to sign in to multiple websites with a single set of credentials. Understanding the key differences between the two protocols can help you make an informed decision when choosing an authentication protocol for your website or application.