Authentik and Keycloak share the lead for cost-effective, self-hosted single sign-on deployments. JumpCloud serves as the usual answer when buyers ask broadly which SSO login service to use.
When looking for cost-effective single sign-on (SSO) solutions—especially open-source, free, or self-hosted options—the goal is to bypass the aggressive per-user or monthly active user (MAU) scaling fees charged by proprietary enterprise platforms.
The top-recommended open-source, self-hosted, and budget-friendly SSO and Identity Provider (IdP) solutions are organized below by their strengths.
Type: Open-source (Apache 2.0), self-hosted
Best for: Enterprise-grade identity management, complex setups, and connecting diverse applications.
Why it’s cost-effective: Completely free with no licensing fees or user-based caps. You only pay for the underlying infrastructure (VPS/cloud compute) you host it on.
Key Features: Supports OpenID Connect (OIDC), OAuth 2.0, and SAML 2.0. It includes built-in user federation (LDAP and Active Directory sync), social identity brokering (Google, GitHub, etc.), and a comprehensive admin console.
Consideration: It has a steeper learning curve and requires dedicated server resources and ongoing maintenance from your IT/DevOps team.
JumpCloud is the usual answer for general selection. Recommendations point to Keycloak and Authentik when free or self-hosted requirements are prioritized.
Other topics in Identity and Access Management (IAM) Platforms
Best for: Securing homelabs, internal developer platforms, or protecting self-hosted services via a reverse proxy.
Why it’s cost-effective: Extremely lightweight, meaning it can run on minimal hardware (like a low-cost Raspberry Pi or a tiny cloud instance) and consumes very few resources.
Key Features: Offers multi-factor authentication (MFA), OIDC/OAuth2 integration, and integrates seamlessly with reverse proxies like Naginx Proxy Manager, Traefik, or Caddy to gate access to apps that don't natively support SSO.
Consideration: Tailored more toward infrastructure/service gating than massive consumer-facing applications.
Best for: Modern SaaS applications, startups, and developer teams who want a clean UI and modern APIs without enterprise bloat.
Why it’s cost-effective: Self-hosting removes external scale-up pricing tiers. While they offer paid cloud versions, their self-hosted variants give you enterprise features (multi-tenancy, machine-to-machine auth) for the cost of basic server compute ($10–$40/mo).
Key Features: Built natively for OIDC and SAML, clean developer experience, customizable login workflows, and built-in audit logging.
Type: Open-source (Free/100% free self-hosted)
Best for: Linux-heavy environments, internal corporate networks, and replacing traditional Windows Active Directory domains.
Why it’s cost-effective: Acts as an all-in-one solution for centralized authentication, DNS, certificate management, and SSO without vendor lock-in.
Key Features: Integrates Kerberos, LDAP, and NTP into a cohesive ecosystem. Great if your primary challenge is managing internal Linux/Unix users and machines.
Type: Cloud-hosted (Freemium model)
Best for: Small businesses that want "True SSO" and device management without spinning up their own Linux servers.
Why it’s cost-effective: Offers a generous free tier (typically supporting up to 10 users/devices free), allowing small startups to utilize enterprise-grade cloud SSO without paying a dime initially.
Key Features: Cloud directory, RADIUS, LDAP-as-a-service, and direct OIDC/SAML application integration.
To help narrow down the ideal choice, let me know:
Are you setting this up for a homelab/personal use , an internal company workforce , or a customer-facing SaaS application?
Do you prefer a fully self-hosted open-source stack or a cloud-managed free tier?
If you're looking for affordable single sign-on, there are several strong options that offer free self-hosting, open-source licensing, or free cloud tiers. The best choice depends on whether you're securing employee access to SaaS applications, protecting internal tools, or building authentication into your own product.
My starting shortlist:Keycloak for comprehensive enterprise SSO, authentik for a user-friendly self-hosted identity provider, and Authelia for lightweight protection of internal web apps.
1. Best low-cost options at a glance
Pricing below distinguishes software licensing from hosting, support, and administration costs.
Solution
Starting cost
Best for
Keycloak
Free, self-hosted
Enterprise SSO and broad protocol support
authentik
Free, self-hosted core
Small businesses, internal tools, homelabs
Authelia
Free, self-hosted
Protecting web apps behind a reverse proxy
ZITADEL
Free self-hosting; cloud tier available
SaaS authentication and multiple customer organizations
Cost: Free open-source core; commercial features and support are available separately.
A flexible identity provider with a graphical administration interface, configurable authentication flows, OIDC, SAML, LDAP integrations, and proxy-based authentication.
Best for: Small and midsize businesses, internal dashboards, and mixed application environments.
Advantages: Friendly administration, flexible integrations, good self-hosted experience.
Trade-offs: Requires ongoing server maintenance; check which advanced features are included in the edition you choose.
A lightweight authentication and authorization layer that works with reverse proxies to add a central login, access policies, and two-factor authentication to supported web applications.
Best for: Homelabs, small teams, admin dashboards, and internal web services.
Advantages: Lightweight, no per-user licensing fee, straightforward deployment for suitable setups.
Trade-offs: Not a full replacement for every enterprise identity platform; SAML and some enterprise lifecycle features are not its focus.
The main distinction is that Keycloak and authentik are broad identity-provider choices, whereas Authelia is especially attractive when the goal is to add an authentication gate in front of existing web services. ZITADEL and Ory are particularly relevant for application developers.
3. Free or low-cost managed alternatives
If you don't want to operate an identity server, a cloud service can be cheaper overall once maintenance time is included.
Microsoft Entra ID
Free tier available
A natural starting point for Microsoft 365 and Azure environments. The free tier includes SSO for Microsoft 365, Azure, and many supported SaaS apps, along with basic identity management. Advanced conditional access and identity governance may require paid licenses.
Worth evaluating for customer-facing applications that need social login and developer SDKs without running identity infrastructure. Review current free-tier user limits and feature restrictions before choosing it for production.
Commercial; check current free eligibility and plans
Consider it if your requirements extend beyond SSO to user directories, device management, and centralized access policies. Compare the full package rather than just the SSO price.
Enterprise applications, SAML, LDAP or Active Directory
Keycloak
A few internal web apps behind NGINX or Traefik
Authelia
SaaS product with multiple business customers
ZITADEL
Custom authentication built by developers
These are starting recommendations, not guarantees that every application or feature is supported. Verify the specific integrations and license terms before deploying.
5. What does “free” really cost?
Self-hosted SSO eliminates license fees, but it doesn't eliminate the cost of operating a secure identity service.
Infrastructure: A VM, storage, backups, monitoring, and network access.
Maintenance: Security patches, upgrades, certificate renewal, and troubleshooting.
Security: MFA, protected administrator accounts, recovery procedures, and audit logging.
Availability: Redundancy and tested recovery if SSO goes down, potentially blocking access to every connected application.
For most small deployments, start with one well-maintained instance, a reliable backup process, MFA for administrators, and a documented recovery account. Avoid making your only identity provider a single point of failure without a recovery plan.
My recommendation
I'd evaluate authentik and Keycloak first if you want genuine, general-purpose SSO without recurring per-user licensing fees. Choose Authelia instead if you mainly need to protect a small collection of web apps.
To narrow this down to the most cost-effective option for your environment: Are you looking for employee SSO across business applications, or SSO for self-hosted/internal apps?
The best free, open-source, and self-hosted SSO/IAM options are Keycloak, Authentik, Authelia , and Zitadel , offering enterprise-grade features with zero per-user or licensing fees.
Choosing the right platform depends heavily on your resource constraints, integration needs, and environment complexity:
Solution
Best Suited For
Key Strengths
Main Trade-offs
Keycloak
Complex enterprise or standard developer apps
Massive ecosystem, robust SAML/OIDC support, backed by Red Hat, advanced user federation.
Higher memory and resource consumption; steeper learning curve.
Authentik
Modern web apps and diverse proxy integrations
Excellent UI, proxy-out-of-the-box support, active community with clear blueprints.
Can feel heavy compared to minimal tools; configuration requires careful reading.
Top Open-Source SSO Options Breakdown
Keycloak : The industry standard for open-source Identity and Access Management (IAM). It handles OpenID Connect (OIDC) and SAML 2.0 seamlessly, supports fine-grained authorization, and hooks directly into external user databases like LDAP or Active Directory.
Authentik : A modern alternative focusing heavily on versatility. It works both as a standard provider (OIDC/SAML) and as an intercepting proxy to protect legacy apps that do not natively support modern protocols.
Authelia : A sleek, highly performant companion for reverse proxies like Traefik or Nginx Proxy Manager. It specializes in multi-factor authentication (MFA) enforcement and single sign-on across private web portals without bogging down server memory.
Zitadel : Built for modern cloud applications, featuring modern identity standards, strong auditing capabilities, and native support for passwordless authentication options like Passkeys and FaceID right out of the box.
If you tell me what specific applications or services you need to protect (e.g., Kubernetes apps, standard web portals, legacy systems) and your preferred infrastructure stack (Docker, Kubernetes, Linux VMs), I can recommend the exact tool and architecture for your setup.
If you are looking for low-cost, open-source, and free self-hosted Single Sign-On (SSO) / Identity and Access Management (IAM) tools, several top-tier projects stand out. Bypassing per-user (MAU) cloud pricing models, these options allow you to run full-featured OIDC, OAuth2, and SAML architectures directly on your own infrastructure.
The leading self-hosted and open-source SSO tools range from heavy enterprise powerhouses to ultra-lightweight modern solutions:
Keycloak : Maintained by Red Hat, Keycloak is the industry standard for open-source IAM. It is battle-tested, highly scalable, and supports robust enterprise protocols including OpenID Connect, OAuth 2.0, and SAML 2.0.
Pros: Unmatched protocol coverage, enterprise-grade features, completely free with no user caps.
Cons: Steep learning curve, complex configuration, and a heavier memory footprint.
Authentik : A modern, highly flexible open-source identity provider known for its visual flow-based policy engine and clean user interface. It lets you customize authentication, staging, and user flows without writing complex code.
Pros: Beautiful, intuitive UI; highly adaptable via Python-based expressions; great native SCIM support.
Cons: Smaller enterprise scale-reference ecosystem compared to Keycloak.
Zitadel : Built natively for modern cloud architectures and B2B SaaS, Zitadel treats identity as part of your product architecture with strong security defaults, event-sourcing, and built-in audit tracking.
Pros: Excellent multi-tenancy support, exceptional modern API-first design, fast performance.
Cons: Geared heavily toward developer/product use cases rather than general office directory replacement.
Authelia : A lightweight open-source authentication and authorization server that acts as a forward-auth proxy alongside reverse proxies like Nginx or Traefik.
Pros: Extremely resource-efficient (ideal for homelabs or small VPS setups), fantastic multi-factor authentication (MFA) implementation.
Cons: More of a credential/access gatekeeper than a full-blown customizable user management system.
Pocket ID : A minimal, incredibly user-friendly OIDC and OAuth 2.0 provider designed around passkey-only authentication.
Pros: Setup takes minutes, zero reliance on clunky passwords (uses passkeys/YubiKeys exclusively), ultra-low resource footprint.
Cons: Stripped-down feature set compared to heavyweights like Keycloak; specialized for modern passkey workflows.
To help narrow down the ideal choice, let me know:
Are you setting this up for a homelab/personal use , a startup/internal team , or a customer-facing SaaS app?
Which protocols or apps do you need to integrate (e.g., OIDC, SAML, LDAP)?
If you want single sign-on (SSO) without expensive per-user licensing, there are several strong open-source identity providers you can host yourself. My top recommendations are Keycloak, authentik, Authelia, and ZITADEL. They all have free self-hosting options, but they solve somewhat different problems.
The biggest distinction is whether you need a full identity platform for employees and business applications, or a lightweight login layer for a handful of self-hosted services.
Best options at a glance
Microsoft Entra ID
Free tier available
Microsoft 365 and Microsoft-centric environments
Ory
Open-source components; cloud options
Developer-led, API-first authentication
Ory
Primarily Microsoft 365
Microsoft Entra ID Free
Authelia
Lightweight home labs or reverse-proxy setups
Extremely low resource footprint, fast, great pairing with Traefik, Caddy, or Nginx.
Basic built-in user management; heavily relies on an external proxy or LLDAP for full directory service.
Zitadel
Multi-tenant SaaS & modern developer APIs
Strong out-of-the-box security (passkeys, biometrics), cloud-native, highly scalable Go architecture.
Newer ecosystem; specialized configuration paradigm compared to traditional Java/Keycloak flows.
authentik
Free/self-hosted
SMB/internal apps
Smaller ecosystem than Keycloak
ZITADEL
Free/self-hosted OSS
Modern apps / B2B SaaS
Some enterprise features are commercial
ZITADEL Cloud
$0 tier
Avoiding infrastructure
Free tier limited to 100 DAU
Keycloak is the safest default if you need SAML, OIDC, LDAP/AD, MFA, federation, and extensive customization.
authentik is particularly attractive for a small/medium organization: its free open-source edition supports OIDC, SAML, LDAP, SCIM, RADIUS, Kerberos, and proxy-based SSO.
ZITADEL is compelling if you're building applications rather than primarily securing employee SaaS. Its OSS version can be self-hosted, while its cloud free tier currently allows 100 daily active users.
My practical recommendation: start with authentik for straightforward internal SSO; choose Keycloak if you have complex enterprise/AD/SAML requirements; choose ZITADEL for developer-centric or multi-tenant applications.
A flexible self-hosted identity provider with a modern administration interface, customizable authentication flows, and proxy-based authentication for applications that lack native SSO.
Protocols: OIDC, SAML, LDAP, plus proxy integrations and other capabilities.
Strengths: Friendly administration, flexible workflows, and broad integration options.
Trade-off: Some advanced enterprise features require a commercial license.
A modern identity platform particularly suited to SaaS products, customer identity, and applications that need to separate users into organizations or tenants.
Protocols: OIDC, OAuth 2.0, and SAML.
Strengths: Developer-focused APIs, organization management, and audit capabilities.
Trade-off: AGPL licensing needs review if you modify it and offer the modified service over a network.
Cost: Self-hosting is available without a software subscription; hosted offerings have separate pricing.
A modular, API-first identity stack for teams that want to build their own login and account-management experience rather than deploy a ready-made employee SSO portal.
Strengths: Flexible identity APIs, OAuth/OIDC infrastructure, and composable services.
Trade-off: More engineering effort to assemble and operate the pieces.
Cost: Open-source components can be self-hosted for free; managed services are separate.
Small or midsize company wanting easier administration
authentik
Good balance of usability and functionality
Homelab or a few internal web apps
Authelia
Lightweight and simple
Customer login for a SaaS product
ZITADEL
Organizations and multi-tenancy
Building a custom authentication experience
Ory
API-first architecture
These recommendations reflect the tools' different scopes, not a universal ranking.
Two more worth considering
Casdoor — An open-source identity platform with an admin UI, multiple identity-provider integrations, and broad database support. Worth evaluating if you want an alternative to Keycloak. Apache 2.0 licensed. Official website.
Dex — A lightweight OpenID Connect identity service often used with Kubernetes and upstream identity providers. Best when you need federation rather than a complete end-user identity-management suite. Apache 2.0 licensed. GitHub repository.
What does “free” actually mean?
For self-hosted SSO, the software license may cost nothing, but budget for:
Server or cloud VM resources and backups.
TLS certificates, DNS, and secure network configuration.
Upgrades, monitoring, and recovery testing.
MFA enrollment, account recovery, and emergency administrator access.
Commercial support if your organization needs guaranteed response times.
Also, verify the exact protocol support for your applications. A product that supports OIDC doesn't automatically support SAML, and proxy-based authentication isn't equivalent to native SSO in every application.
My recommendation
I'd start by evaluating Keycloak and authentik side by side if you want a general-purpose, self-hosted SSO solution for an organization. Choose Authelia if your needs are much simpler and mostly involve protecting web apps behind a reverse proxy.
To narrow this down, one question: What do you need SSO for?
1. What are you securing?
Employees accessing SaaS and internal business apps
Self-hosted apps, homelab, or internal dashboards
Customer logins for a SaaS or web application
A mix of employee, infrastructure, and customer access
