Software Alternatives & Startups

Phase Two VS IdentityServer

Compare Phase Two VS IdentityServer and see what are their differences

Phase Two

Fully managed, multi-region, high-availability, Keycloak deployments with top extensions to run for any enterprise. 99.95% uptime SLA. 24/7 support. Built by top Keycloak experts and contributors.

Rating
0 reviews
IdentityServer

An open-source, standards-compliant, and flexible OpenID Connect and OAuth 2.x framework for ASP.NET Core

Rating
0 reviews
Pricing
Open source

Which is more popular?

Based on our record, IdentityServer seems to be more popular. It has been mentioned 7 times since March 2021.

social mentions
0 vs 7
SSO popularity
44% vs 56%
alternatives listed
45 vs 50

Base details

Website, pricing, platforms and company facts side by side.

Phase Two
IdentityServer
Website phasetwo.io duendesoftware.com
Pricing
Open source
Listed in

Features and specs

What each product offers, as listed by its team.

Phase Two 5 features
IdentityServer 6 features
  • Enhanced Multi-Tenancy for Keycloak
    Phase Two provides robust multi-tenancy support on top of Keycloak, allowing organizations to manage multiple tenants, organizations, and teams within a single Keycloak instance, which is not natively straightforward in standard Keycloak.
  • Free and Open Source Extensions
    Phase Two offers many of its extensions and features as open-source projects, making it accessible for developers and organizations who want to self-host and customize their identity management solution without vendor lock-in.
  • Managed Keycloak Hosting
    Phase Two provides a managed hosting option for Keycloak, reducing the operational burden of maintaining, upgrading, and scaling Keycloak infrastructure, which can be complex and time-consuming for teams without dedicated DevOps resources.
  • Easy Onboarding and Developer Experience
    Phase Two simplifies the setup process with quick-start guides, pre-built extensions, and a streamlined dashboard that makes it easier for developers to integrate SSO, identity management, and organization features into their applications compared to raw Keycloak configuration.
  • Enterprise SSO and Identity Provider Support
    Phase Two adds convenient support for enterprise SSO connections, allowing customers to easily configure identity provider connections (such as SAML and OIDC) for their organizations, which is a common B2B SaaS requirement that can be tedious to set up in vanilla Keycloak.

Possible disadvantages

  • Dependency on Keycloak Ecosystem
    Since Phase Two is built on top of Keycloak, it inherits Keycloak's complexity, upgrade challenges, and potential breaking changes. Users are tied to the Keycloak release cycle and must deal with its sometimes steep learning curve.
  • Limited Community and Ecosystem Compared to Alternatives
    Phase Two has a smaller community and ecosystem compared to more established identity platforms like Auth0, Okta, or even standalone Keycloak. This can mean fewer third-party integrations, community resources, and troubleshooting support.
  • Potential Vendor Lock-in on Managed Features
    While the open-source extensions are available for self-hosting, some of the managed platform features and the convenience of the hosted dashboard may create a degree of dependency on Phase Two's specific tooling and infrastructure.
  • Limited Documentation and Resources
    As a relatively newer and smaller platform, Phase Two's documentation, tutorials, and community-generated content can be less comprehensive compared to larger identity providers, which may slow down development and troubleshooting for less experienced teams.
  • Pricing Transparency for Enterprise Tiers
    While Phase Two offers a free tier, the pricing for higher-tier managed hosting and enterprise features may not be fully transparent or may become costly as usage scales, making it difficult for organizations to predict long-term costs compared to some competitors with clearer pricing models.
  • 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

  • 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.

Analysis

An editorial look at what each product does well and who it suits.

Phase Two
IdentityServer

Overall verdict

  • Phase Two is a solid, developer-friendly identity and access management solution built on top of Keycloak, offering enterprise-grade authentication with multi-tenancy and SSO capabilities at a competitive price point.

Why this product is good

  • Built on the proven open-source Keycloak platform, giving you flexibility and avoiding vendor lock-in
  • Strong multi-tenancy support with organizations, making it well-suited for B2B SaaS applications
  • Supports modern authentication standards like OAuth2, OIDC, and SAML for enterprise SSO
  • Offers both managed cloud hosting and self-hosted deployment options for flexibility
  • Developer-focused with good API support, extensions, and documentation
  • More cost-effective than many enterprise IAM competitors like Auth0 or Okta

Recommended for

  • B2B SaaS companies needing multi-tenant authentication and organization management
  • Development teams that want the power of Keycloak without managing all the infrastructure themselves
  • Businesses requiring enterprise SSO (SAML, OIDC) for their customers
  • Startups and scale-ups looking for a cost-effective alternative to Auth0 or Okta
  • Organizations that value open-source foundations and want to avoid vendor lock-in

No analysis of IdentityServer yet.

Videos

Walkthroughs and reviews on video.

Phase Two 1 video + Add
IdentityServer 2 videos + Add

Marvel Phase Two - A Retrospective

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

More videos

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

Category popularity

How often each product is chosen within a category, 0–100% relative to the other.

Score bands 0–20 21–40 41–50 51–60 61–100
Phase Two
IdentityServer
44% 44%
SSO
56% 56%
35% 35%
65% 65%
100% 100%
0% 0%

User comments

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Reviews and articles

External articles and on-site reviews we used to compare the two products.

Phase Two no reviews yet
IdentityServer no reviews yet

We have no reviews of Phase Two yet. Be the first one to post

Social recommendations and mentions

Recommendations tracked on public social media and blogs since March 2021.

Phase Two 0 mentions
IdentityServer 7 mentions

Tracking Phase Two since Jun 2026.

  • Identity server 4
    Its deprecated in favor of Duende Identityserver which introduced a license model. Source: almost 3 years 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... Source: almost 4 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 / almost 4 years ago

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Alternatives to Phase Two and IdentityServer

When comparing Phase Two and IdentityServer, you can also consider the following products.