The best 5 SSO providers to power your SaaS app in 2025

Secure and seamless authentication is a fundamental requirement for any serious SaaS platform.

Customers expect enterprise ready SSO, and providers are racing to keep up with shifting standards, compliance requirements, and developer needs. SSO is the cornerstone of secure, seamless authentication, but building it in-house rarely makes sense for a growing startup that needs to focus on its core product. Instead, most teams choose to integrate with a specialized SSO provider.

In this article, we’ll cover why SSO is essential, how to evaluate providers, and our curated list of the five best SSO solutions available in 2025.

Do you really need an SSO provider?

With so many authentication libraries and open-source projects available, it’s tempting to stitch together your own SSO stack and call it a day. But getting authentication right is deceptively complex, and the cost of mistakes can be high.

Building SSO in-house means spending weeks (or months) on initial implementation, then redoing the work for each new enterprise customer, because every client’s Identity Provider (IdP) is different. And that’s just the start, you’ll also need to maintain these integrations, keep them secure, and update them as standards evolve.

Here’s why a dedicated SSO provider is the smarter choice for most SaaS teams:

• Avoid the complexity: A good SSO provider handles the messy parts for you: auth servers, signing keys, token formats, and yes, even the dreaded SAML XML assertions. You focus on your core product instead of wrestling with authentication internals.
• Stronger security by default: Rolling your own means you also own the responsibility of keeping security measures up to date. Providers invest heavily in best practices like leaked password detection, adaptive authentication, and other modern safeguards, so you benefit from cutting-edge protection without building it yourself.
• Support for every IdP your customers use: Enterprise buyers are all over the map when it comes to IdPs. You might start with Okta and Microsoft Entra ID, but sooner or later, you’ll meet customers on PingFederate, CyberArk, Shibboleth, and others you’ve never heard of. A mature SSO provider already supports dozens (or hundreds) of IdPs out of the box.
• Lower total cost of ownership: It’s easy to look at per-user pricing and think, “We could just build this ourselves.” But when you factor in engineering salaries, ongoing maintenance, and the inevitable rush projects to integrate new IdPs, a dedicated provider almost always costs less in the long run.
• Higher reliability: Authentication is the front door to your app. If it’s down, your users are locked out. In-house systems are more prone to downtime during updates or incidents. Reputable SSO providers deliver high uptime SLAs and handle maintenance without locking out your customers.

If you’re serious about moving upmarket, an SSO provider gives you peace of mind, enterprise-grade reliability, and broad IdP coverage, all without slowing your team down.

Check out our Build vs Buy series for a detailed analysis on how building complex features in-house, like SSO and SCIM, can significantly delay enterprise adoption.

What to look for in an SSO provider

Choosing the right SSO provider is more than just ticking the “supports SAML” box. The right partner will save your team time, scale with your business, and keep enterprise customers happy from day one. Here are the four key areas to evaluate:

1. Ease of integration

Integration speed can make or break your rollout. Look for:

• Well-documented APIs and SDKs in the languages you use.
• Clear onboarding tools you can share with your customer’s IT team.
• Responsive technical support for when things get tricky.

A provider that’s easy to work with will pay off every time you onboard a new enterprise client.

2. Pricing that fits your model

Most providers price either by monthly active users (MAUs) or per connected organization. Pick the wrong one, and your costs can balloon unexpectedly.

• Compare multiple providers. Prices vary dramatically, even with the same model.
• Model your projected growth before committing.

Remember: authentication isn’t a commodity market. Pricing differences can be huge.

3. Proven scalability

Enterprise customers don’t grow like normal SaaS accounts; one deal can add thousands of users overnight. Your SSO provider needs to handle that without breaking a sweat.

• Look for a track record of high-scale deployments.
• Prioritize providers offering a 99.99%+ uptime SLA.

4. Extra features that matter

SSO is the foundation, but enterprise buyers often expect more. The right extras can help close deals and make your product stickier:

• SCIM provisioning for automatic user lifecycle management.
• Audit log streaming into your customer’s IdP.
• Additional login methods like magic links or multi-factor authentication (MFA).

These “bells and whistles” aren’t just nice-to-haves; they can be the deciding factor when your app is evaluated against competitors.

The best SSO providers

Here’s our curated list of the five most notable SSO solutions on the market, starting with the one we know best.

• WorkOS is the overall best SSO provider, with the easiest integration, best pricing, support for every major IdP, and plenty of extra features.
• Auth0 if you want a mature, dependable MAU-based SSO and you’re willing to pay for it.
• Okta if you need an enterprise-grade IAM platform with broad governance features (but be prepared for higher costs and more complexity than most SaaS teams require).
• Microsoft Entra ID if your customers live in the Microsoft ecosystem and you want seamless integration with Microsoft 365, Azure, and related services.
• Keycloak if you still want an open-source solution, but a much fuller solution than an SSO NPM library.

1. WorkOS: Enterprise SSO without the enterprise hassle

WorkOS is designed from the ground up to make adding enterprise SSO and user provisioning to your SaaS app fast, developer-friendly, and scalable. With simple APIs, robust documentation, and native support for SAML, OIDC, SCIM, and more, WorkOS bridges the gap between enterprise IT requirements and modern SaaS development.

Pros

• Extremely fast time-to-market, most integrations in hours, not weeks.
• Clean, modern APIs and SDKs for multiple languages.
• WorkOS integrates seamlessly with every identity provider (Okta, Microsoft Entra ID, Google Workspace, Ping, and more), so you can onboard enterprise customers no matter what stack they use.
• Enterprise ready features: SCIM provisioning, audit logs, role-based access, self-serve onboarding, real-time protection against bots and abuse, and more.
• Transparent pricing that scales with your growth.
• Excellent developer experience with sandbox environments and clear docs.
• Unlike larger IAM platforms that prioritize enterprise IT departments, WorkOS is laser-focused on helping SaaS companies sell to enterprises, ensuring roadmap alignment with your needs.

Cons

• Not a full IAM suite. WorkOS focuses on enterprise features like SSO, automated user provisioning, access control, and audit logs, not the entire enterprise IT stack. Full IAM suites (like Okta Workforce Identity or Microsoft Entra ID) include extra features for managing internal employees, devices, and compliance, but for most SaaS teams, that added complexity isn’t necessary.

Pricing

Usage-based, transparent pricing with a generous free tier for development and testing.

2. Auth0: Developer-focused identity platform

Auth0 (acquired by Okta) is an identity platform popular with developers for quickly integrating authentication and SSO into apps. It offers broad identity protocol support and a marketplace of prebuilt integrations.

Pros

• Developer-frie
• Supports all the major standards (SAML, OIDC, OAuth), along with support for social logins and passwordless authentication.
• Flexible rules and hooks for customization.
• Large ecosystem of integrations.

Cons

• Pricing can escalate quickly at scale. Core features like enterprise SSO, advanced MFA, and anomaly detection are locked behind higher tiers, and MAU-based pricing can become unpredictable as you grow.
• More complexity than many small teams need. The platform is powerful but can feel heavy, requiring developers to learn its proprietary rules engine, pipelines, and dashboard quirks just to get basic SSO working.
• Now part of Okta, meaning roadmaps and support priorities are tied to a larger enterprise product strategy. Since the acquisition, many customers have noted longer resolution times and a tighter alignment with Okta’s enterprise-first strategy.
• Vendor lock-in risk. Custom rules and extensions are written specifically for Auth0, making migration to another provider more difficult later on.

Pricing

Tiered pricing starting with a free developer plan, but jumps significantly for enterprise SSO and advanced features.

3. Okta: Enterprise identity giant

Okta is one of the most established names in identity and access management, offering a vast range of security and compliance features. It’s a powerhouse for enterprise IT departments managing thousands of employees.

Pros

• Extremely robust feature set for enterprise governance. Okta covers the full IAM spectrum, from SSO and MFA to lifecycle management, identity governance, and privileged access, making it a strong fit for complex enterprise IT needs.
• Massive integration network. With thousands of pre-built connectors, Okta can integrate with nearly any SaaS or on-premises application your enterprise customers use.
• Adaptive MFA and strong compliance track record.
• Established enterprise reputation.

Cons

• Overkill for most SaaS teams that just need SSO for their customers. Okta is built as a full enterprise IAM platform, so if you only need customer-facing SSO, you’ll be paying for (and navigating) features you’ll never use.
• Steeper learning curve and implementation time. Setting up SSO through Okta often requires specialized knowledge of their ecosystem, and onboarding enterprise customers can be slower compared to lighter providers.
• Higher total cost of ownership. Okta charges separately for modules like SSO, MFA, lifecycle management, and provisioning. Costs add up quickly, especially when compared to focused solutions.
• Okta’s roadmap and product design are optimized for large corporate IT departments, not startups or SaaS teams building customer apps.

Pricing

Separate pricing for each module; SSO alone starts around $2/user/month, but full functionality can cost much more.

4. Microsoft Entra ID (formerly Azure AD): Microsoft ecosystem powerhouse

Microsoft Entra ID is the go-to choice for organizations deeply embedded in Microsoft 365 and Azure. It offers SSO across Microsoft products and thousands of third-party apps.

Pros

• Seamless for organizations already using Microsoft infrastructure.
• Strong compliance and security controls. Backed by Microsoft’s enterprise security investments, it meets global regulatory requirements (GDPR, HIPAA, FedRAMP, etc.).
• Wide protocol support. Supports SAML, OIDC, OAuth2, WS-Fed, and SCIM, making it compatible with a broad range of enterprise applications.
• Enterprise credibility. Trusted by Fortune 500 companies and often already in place within customer IT environments, reducing procurement friction.

Cons

• Best suited for Microsoft-centric environments. Integration feels smooth if your customers use Microsoft services, but less streamlined if they don’t.
• Entra ID can be difficult to configure for non-Microsoft SaaS apps, and licensing tiers are notoriously confusing.
• Innovation and roadmap tend to prioritize Microsoft-first use cases over broader SaaS developer needs.
• Pricing and licensing can be confusing and costs scale quickly. Advanced identity features are locked behind premium tiers (~$6+/user/month), which can add up fast.

Pricing

Included in some Microsoft 365 subscriptions; premium tiers for advanced SSO and identity features start at ~$6/user/month.

5. Keycloak: Open-source identity & access management

Keycloak is the leading open-source IdP, offering SSO, MFA, and identity brokering under the Apache 2.0 license. It’s highly customizable and self-hostable.

Pros

• Completely open-source and free. No per-user or per-organization licensing fees, making it attractive for budget-conscious teams.
• Full protocol and feature coverage. Supports SAML, OIDC, OAuth2, MFA, identity brokering, role-based access control, and more.
• Highly flexible, extensible architecture. You can extend authentication flows, write custom providers, and tailor login experiences through themes and APIs.
• An active open-source community and Red Hat backing. This ensures ongoing maintenance, enterprise-grade contributions, and a large pool of community extensions.

Cons

• Self-hosted overhead. You’re responsible for deployment, scaling, monitoring, and patching, which can demand significant DevOps resources.
• Steeper learning curve for deployment and maintenance. Configuration and customization can be complex, especially for teams new to enterprise identity protocols.
• Requires internal DevOps expertise to keep running smoothly. Staying up-to-date with security patches and feature releases requires ongoing engineering time.
• While Red Hat offers paid support, the base open-source project lacks the SLAs and customer support enterprises typically expect.

Pricing

Free to use under an open-source license; hosting and maintenance costs vary.

Final thoughts

When choosing an SSO provider for your SaaS app in 2025, the right fit depends on your target audience, infrastructure, and team resources.

• If you want enterprise SSO without the complexity, WorkOS is the fastest path to production.
• If you need deep enterprise governance, Okta delivers (at a cost).
• Auth0 can offer flexibility, but it may be more than you need.
• Microsoft Entra ID is great in a Microsoft-heavy world.
• Keycloak is powerful for teams that want open-source control, but it demands internal bandwidth.

In short: start with WorkOS, and you’ll likely ship enterprise SSO faster, with fewer headaches.

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