Software Alternatives, Accelerators & Startups

FusionAuth VS IdentityServer

Compare FusionAuth VS IdentityServer and see what are their differences

FusionAuth logo FusionAuth

FusionAuth is a CIAM platform that is 100% free for unlimited users.

IdentityServer logo IdentityServer

An open-source, standards-compliant, and flexible OpenID Connect and OAuth 2.x framework for ASP.NET Core
  • FusionAuth Landing page
    Landing page //
    2023-02-10

FusionAuth adds authentication, authorization, user management, reporting, analytics and much more in minutes not months.

  • IdentityServer Landing page
    Landing page //
    2023-02-03

FusionAuth features and specs

  • Comprehensive Feature Set
    FusionAuth provides a wide range of authentication and authorization features including OAuth, SSO, MFA, social login, and user management.
  • Developer Friendly
    FusionAuth offers extensive documentation, APIs, and SDKs that make it easy for developers to integrate and customize.
  • Self-Hosted and SaaS Options
    FusionAuth can be deployed on-premises or accessed as a cloud service, providing flexibility based on organizational needs.
  • Scalable
    FusionAuth is designed to handle millions of users, making it suitable for both small-scale and enterprise-grade applications.
  • Good Community Support
    There is a vibrant community and responsive support team that can help with troubleshooting and advice.
  • Free Tier
    FusionAuth offers a free version that includes a substantial set of features, which is beneficial for startups and small projects.

Possible disadvantages of FusionAuth

  • Complex Initial Setup
    The initial configuration and setup can be complex and time-consuming, particularly for users who are not familiar with authentication systems.
  • Cost
    While there is a free tier, the advanced features and higher usage plans can become costly for larger applications.
  • Resource Intensive
    Self-hosting FusionAuth may require significant server resources, which can be a drawback for smaller organizations.
  • Learning Curve
    Given its comprehensive feature set, there can be a steep learning curve for new users to fully leverage all the capabilities.
  • Limited Customization for SaaS
    The SaaS version may have limitations in customization and control compared to the self-hosted option.

IdentityServer features and specs

  • Open Source Foundation
    IdentityServer is built on an open-source foundation. It has been widely used and developed by a community, ensuring transparency, reliability, and continuous improvements.
  • Comprehensive Protocol Support
    It supports industry standards such as OpenID Connect and OAuth 2.0, which are essential for authentication and authorization processes.
  • Customizability
    IdentityServer offers high levels of customizability, allowing developers to tailor authentication and authorization features to specific application needs.
  • Enterprise-Ready
    Designed to handle complex enterprise scenarios with robust performance and scalability options suitable for large-scale applications.
  • Strong Security Features
    Includes several security mechanisms to protect sensitive data, such as secure token storage and advanced encryption options.
  • Comprehensive Documentation
    Provides extensive documentation and resources, helping developers to implement and troubleshoot the server effectively in their systems.

Possible disadvantages of IdentityServer

  • Licensing Cost
    Since its transition from IdentityServer4 to a non-OSS model under Duende Software, organizations need to purchase a license for commercial use, impacting budget-conscious projects.
  • Complexity
    Can be complex to set up and configure properly, especially for teams that are new to security protocols like OAuth and OpenID Connect.
  • Maintenance Overhead
    Requires ongoing maintenance and updates to ensure security and compatibility with evolving protocols, which can be resource-intensive.
  • Potential Overhead for Small Projects
    May be overkill for smaller projects or teams that do not require robust authentication systems, where simpler solutions might suffice.
  • Community vs. Commercial Transition
    The switch from a community-driven open-source project to a commercial product may alienate previous users who relied on its open-source nature.

FusionAuth videos

Replicating StackOverflow login with FusionAuth

More videos:

  • Demo - FusionAuth Demo

IdentityServer videos

Federated Identity: An intro to OAuth2, Open Id Connect & Duende IdentityServer 5 | Anthony Nguyen

More videos:

  • Review - There's an IdentityServer in my API project - Anders Abel

Category Popularity

0-100% (relative to FusionAuth and IdentityServer)
SSO
78 78%
22% 22
Identity Provider
70 70%
30% 30
Identity And Access Management
Authentication
100 100%
0% 0

User comments

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Reviews

These are some of the external sources and on-site user reviews we've used to compare FusionAuth and IdentityServer

FusionAuth Reviews

10 Best Auth0 Alternatives and Similar Platforms
Like Auth0, FusionAuth is a powerful user management solution with a lot more to offer. Getting started and setting up FusionAuth takes no time because it is compatible with databases, such as Java and C#.
IAM: A comparison of open-source tools
/ Digitalberry news / IAM: A comparison of open-source toolsIAM: A comparison of open-source toolsWhy use an Identity Provider (IdP)?Comparative study of Identity Providers (IdP)1. Our team’s first choice: Keycloak2. In second place of our comparative study: Gluu3. Special mention: FusionAuthDiscover our expertiseContact our experts
Auth0 and FusionAuth: A Tale of Two Solutions
One of the biggest differences between Auth0 and FusionAuth is cost. FusionAuth is free for unlimited users. No strings, gimmicks, or tricks. No cost increases when you hit a certain Monthly Active User threshold. Much like a database or a web server, secure authentication is so essential that developers should be able to implement it quickly and easily without cost...
Source: fusionauth.io

IdentityServer Reviews

10+ Open-source Single-Sign On (SSO) Solutions
If you are looking for a certified and complaint system to OpenID Foundation, with .Net technologies, then IdentityServer is your answer.
Source: medevel.com
Top 5 Open Source Single Sign-On Software In the Year 2021
IdentityServer is an open source free single sign-on software. It is a cross-platform framework based on OpenID Connect and OAuth 2. Further, this open source software provides central authentication and authorization capabilities for multiple applications. It supports federated identities, multiple flows, and API authorization. Moreover, this self hosting software enables...

Social recommendations and mentions

Based on our record, FusionAuth should be more popular than IdentityServer. It has been mentiond 30 times since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.

FusionAuth mentions (30)

  • Launch HN: Stack Auth (YC S24) – An Open-Source Auth0/Clerk Alternative
    As someone who came from Auth0 and god-awful Amazon Cognito, we've been using FusionAuth for years. Their APIs and SDKs have been amazing to work with. https://fusionauth.io It does what Auth0 does but significantly more cheaper and you can also self-host if you want. I built the Pulimi plugin for it which helps us easily configure it. If you don't use Terraform or Pulumi, they have this really cool kickstart... - Source: Hacker News / 9 months ago
  • Top 6 Open Source Identity and Access Management (IAM) Solutions For Enterprises
    FusionAuth is one of the most decorated and successful open-source IAM solutions. It has been downloaded by more than 10 million customers and hosts over 1 million digital identities. - Source: dev.to / about 1 year ago
  • Evolutive and robust password hashing using PBKDF2 in .NET
    Ideally, I would recommend not handling and storing passwords yourself. It is preferable to use an identity provider (IdP), such as Azure AD B2C, Auth0, or FusionAuth. These systems are designed to manage your users' identity (including their passwords) so you don't have to. You could also use Single Sign-On with cloud providers. - Source: dev.to / over 1 year ago
  • Ask HN: Who is hiring? (August 2023)
    FusionAuth | Senior Java Engineer, Senior TechOps Engineer, Senior Support Engineer | Full-time | Denver CO, USA | https://fusionauth.io FusionAuth is the authentication and authorization platform built for devs, by devs. Our software solves the problem of integrating essential user security without adding risk or distracting from the primary application. Ya know, the one with the features your users want to pay... - Source: Hacker News / almost 2 years ago
  • SSO yet again - Authentik / Authelia / FusionAuth / Teleport / etc.
    But I rarely see a comprehensive comparison that is current for any of them. And then there are others out there like Teleport and FusionAuth. Source: almost 2 years ago
View more

IdentityServer mentions (7)

  • Identity server 4
    Its deprecated in favor of Duende Identityserver which introduced a license model. Source: over 1 year ago
  • How does cookie based authentication work?
    Tokens usually have a lifetime and they are separate from the user's authentication principals like username and password. Unless you are rolling your own form of token provider (not something that would be recommended) the token creation is handled for you. Take a look at https://identityserver4.readthedocs.io/en/latest/ or if your organization makes under 1M in income a year the free version of what Identity... Source: over 2 years ago
  • ImageSharp leaving the .NET Foundation due to licensing change
    I think Duende (Identity Server) handled the situation pretty well. https://duendesoftware.com/products/identityserver > Standard License Pricing. - Source: Hacker News / over 2 years ago
  • Why is authentication such a sh*t show with .NET 6?
    He's referring to IdentityServer 3/4, which was open sourced, and was not owned by Microsoft. That 3rd party is commercializing their work (and to be fair, it's a lot of work) as https://duendesoftware.com/products/identityserver , and has a different commercial licensing model. Source: almost 3 years ago
  • Show HN: Open-Source Identity Server Written in Go (Ory Kratos)
    I think "Identity Provider" is more correct, no? "IdentityServer" is the name of a specific IdP implemented in .NET (formerly OSS as https://identityserver4.readthedocs.io/en/latest, and now as a more commercial form as Duende IdentityServer: https://duendesoftware.com/products/identityserver). - Source: Hacker News / almost 3 years ago
View more

What are some alternatives?

When comparing FusionAuth and IdentityServer, you can also consider the following products

Auth0 - Auth0 is a program for people to get authentication and authorization services for their own business use.

Keycloak - Open Source Identity and Access Management for modern Applications and Services.

ASP.NET Identity - ASP.NET Identity is a membership-based software system designed for the authentication and authorization of the users via building an ASP.NET application.

Okta - Enterprise-grade identity management for all your apps, users & devices

DotNetOpenAuth - DotNetOpenAuth is a free-to-use compiled library that comes with the real support to your site visitor to login with the help of openIDs via getting control of the ASP.NET control onto the page.

LoginRadius - Loginradius is a cloud-based customer identity and access management platform. LoginRadius empowers businesses to deliver a delightful customer experience without compromising security.