Keycloak vs Identityserver4 | What Are The Differences?

Keycloak and Identityserver4 are open source identity providers that offer single sign on services to access resources. Let’s compare these two sso software.

keycloak vs identityserver4


In the near past, we published some blog posts on topics such as How To Leverage SSO System For Better Business Growth, and Top 5 Open Source Single Sign-On Software In the Year 2021. These articles describe widely used open source SSO software and its core impacts on business. However, user management is the most critical aspect of any application. In the modern world of technology, cybersecurity is a hot topic. There are tons of applications that users visit, log in, and log out. A user with multiple sets of credentials is more vulnerable and an easy target of cyberattacks.

Therefore, it is always a good idea to access resources using a single set of credentials. Single sign-on software enables users to log in to multiple applications using a single username and password. Users will log in one time only and can access many applications without login in again. This approach is gaining popularity day by day as the open source community is developing open source identity providers such as Identityserver4 and Keycloak. In this blog post, we will go through the top two open source SSO solutions and will compare the features and scopes as the title suggests Keycloak vs Identityserver4. The following points will be covered.

Brief introduction of Identityserver4

Identityserver4 is an open source SSO software based on OpenID Connect and OAuth 2.0. This free tool is written in the .NET framework (4.5.x) and .NET Core to provide single sign-on services across multiple applications. As an authentication server, it provides a JWT token that can be used to access digital resources. It offers many provisions such as access control for API, user interface customizations, API authorization, and claim-based provider. Further, it is flexible, extensible, and comes with self-hosting capabilities. In addition, it supports multiple flows and federated identities such as Google, Facebook, Twitter, and other social networks.

All the source code of this free single sign-on software is available on Github. Therefore, users can go through all the documentation regarding deployment and development.

What is Keycloak?

Keycloak is another widely used authentication solution. It offers identity and access management using OpenID Connect, OAuth2.0, and SAML 2.0. This free software provides a user-friendly UI to manage users, roles, configurations, and sessions. Moreover, it provides integrations with third-party applications such as LDAP and Active Directory. Users can leverage its centralized user management with enhanced scalability and availability. Above all, it provides client libraries for integrations along with many features such as social logins, user federation, centralized management, password policies, clustering, and adapters. All the source code of this free single sign on software is available on Github. Therefore, users can go through all the documentation regarding deployment and development.

Comparison of Keycloak & Identityserver4

In the section of this Keycloak vs Identityserver4 article, we will compare these two open source identity providers by looking into features and other characteristics by covering the following points.

Community Standing: Both these free SSO software are well-reputed in the community. However, Keycloak has better stats on Github as compared to the Identityserver4. Keycloak has secured 9k plus stars and Identityserver stands with 3k plus stars on Github. As far as documentation is concerned, both free authentication solutions come with comprehensive documentation regarding deployment and documentation.

Features: Firstly, Keycloak and Identityserver4 are based on OpenID Connect and OAuth2.0. However, Keycloak uses another standard protocol SAML2.0. Keycloak comes with a user interface that is customizable and provides integrations with LDAP and Active Directory. Identityserver4 uses OIDC, which is an authentication layer on top of OAuth2 to achieve the SSO. Both the free SSO software come with Docker images and developers can set up using Docker. In addition, Identityserver4 is lightweight as compared to Keycloak.

Tech Stack: As far as the technologies are concerned, Keycloak is mainly written in Java with little input of other languages such as JavaScript, HTML, and some more. Secondly, Identityserver4 is mainly written C# with the input of some other languages such as HTML, and SCSS.

Extensibility: It is one of the main characteristics of any open source software and both these SSO software developer-friendly. These software provide integration with third-party libraries. Moreover, Keycloak offers client adapters written in Java and JavaScript.

Security: Keycloak and Identityserver4 have implemented security mechanisms. Further, Identityserver4 uses bearer tokens for authorization purposes.


This is the end of this Keycloak vs Identityserver4 blog post. We went through some prominent aspects of both free SSO systems and elaborated on some key features. Therefore, you can draw a conclusion yourself about which free single sign-on software is better. This article will surely help you in making the right choice for the right product for your business. Moreover, if you are well aware of your use cases then decision making becomes an easy task. Further, you always opt for software that fits well to your requirements.

Both of these SSO software provide ease to the organization with the ease of accessing resources. Organizations make sure of the availability of resources by installing good single sign-on software. Usres do not need to carry multiple sets of credentials; rather they can use one set of credentials, log in just one time and after that, they can access multiple websites without login in again. It gives confidence, security, and transparency to the whole system

Finally, has been writing on further open source products. Please stay in touch with this Single Sign-On category for regular updates. Moreover, you can follow us on our social media accounts Facebook, LinkedIn, and Twitter.


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