Apereo CAS
Apereo CAS is a free, open-source identity provider and middleware for web authentication and authorization.
What Apereo CAS is
Apereo CAS is a free, open-source identity provider and middleware for web authentication and authorization. It provides a unified sign-in point between web applications and their authentication sources. Supported protocols include CAS, SAML v1 and v2, WS-Federation, OAuth2, OpenID Connect, and REST. Pluggable authentication sources include LDAP, databases, X.509, SPNEGO, JAAS, JWT, RADIUS, and MongoDB. CAS includes session management, single logout, and passwordless multifactor authentication, with providers such as Duo Security, YubiKey, Google Authenticator, FIDO2 WebAuthn, and Twilio. It can also delegate authentication to external providers, including ADFS and OpenID Connect providers. WebAuthn uses public-key cryptography and can use security keys or built-in platform authenticators. Operational features include real-time monitoring of application and system behavior, statistics, and metrics, along with centralized audit and log management. Cross-platform clients include Java, .NET, PHP, Perl, and Apache. CAS is available for API, self-hosted, and web use under the Apache License, Version 2.0, at no cost.
Good
- Supports multiple authentication protocols
- Pluggable authentication sources include LDAP and databases
- Includes single logout and multifactor authentication
- WebAuthn can use security keys or platform authenticators
- Free under the Apache License, Version 2.0
Watch out
- Apereo staff do not provide technical project support
- Project questions are directed to community channels
Who it suits
CAS suits organizations that need a unified authentication point for web applications, including higher education and smaller special-purpose installations. It also supports adaptation for larger companies.
Verdict
CAS provides a broad protocol and authentication-source mix for web sign-in, along with multifactor options and operational monitoring. Organizations should plan to use community resources for technical project support.
Plans and prices
From Apereo CAS's own pricing page, checked 1 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Apereo CAS | Free | Apache License 2.0 · open source |
The facts
Each one read from Apereo CAS's own pages, with the date it was checked.
What it does
- Audience
- CAS originated in higher education and is also described as adaptable to Fortune 500 companies and small special-purpose installations.checked 1 Oct 2026
- Authentication sources
- Pluggable authentication support includes LDAP, databases, X.509, SPNEGO, JAAS, JWT, RADIUS, and MongoDB.checked 1 Oct 2026
- Clients
- Cross-platform client support includes Java, .NET, PHP, Perl, and Apache clients.checked 1 Oct 2026
- Delegated authentication
- CAS can delegate authentication to external providers such as ADFS, Facebook, Twitter, SAML2 identity providers, and OpenID Connect providers.checked 1 Oct 2026
- Integrations
- CAS provides integrations with SAML2 service providers and supports SCIM, reCAPTCHA, and Swagger.checked 1 Oct 2026
- Latest release
- Apereo announced CAS version 7.3.6 on April 8, 2026.checked 1 Oct 2026
- License
- Apereo CAS is distributed under the Apache License, Version 2.0.checked 1 Oct 2026
- Middleware
- CAS operates as middleware between web applications and authentication sources, providing a unified authentication point.checked 1 Oct 2026
- Multifactor providers
- Supported multifactor providers include Duo Security, YubiKey, RSA/RADIUS, Google Authenticator, FIDO2 WebAuthn, Twilio, Inwebo, and CAS Simple.checked 1 Oct 2026
- Operations
- CAS can monitor application and system behavior, statistics, and metrics in real time and centrally manage audits and logs.checked 1 Oct 2026
- Protocols
- The project supports CAS, SAML v1, SAML v2, WS-Federation, OAuth2, OpenID Connect, and REST protocols.checked 1 Oct 2026
- Purpose
- CAS is a multilingual single sign-on solution and open-source identity provider for web authentication and authorization.checked 1 Oct 2026
- Security features
- CAS provides session management, single logout, and passwordless multifactor authentication.checked 1 Oct 2026
- Support
- Apereo staff do not provide technical project support but direct users to project communities and mailing lists, including CAS security, developer, and user lists.checked 1 Oct 2026
- WebAuthn security
- WebAuthn support uses public-key cryptography for phishing-resistant authentication and can use security keys or built-in platform authenticators.checked 1 Oct 2026
Alternatives to Apereo CAS
- 1
Ory
Free planOpen sourceWebAPILinuxmacOS8.4From $770 a year - 2
FusionAuth
Free planAndroidiOSWebAPI8.3From $162 a month - 3
Google Cloud Identity
Free planAndroidiOSWebAPI8.3Free plan - 4
miniOrange Identity and Access Management
Free planAndroidiOSWebAPI8.1From $2 a month - 5
WorkOS
Free planAndroidiOSWebAPI8.1From $99 a month - 6
Descope
Free planAndroidiOSWebAPI7.6From $249 a month