The complete guide to SaaS authentication: Securing your B2B app

In B2B SaaS applications, authentication serves a single fundamental purpose: verifying user identity with certainty. However, authentication solutions need to balance two critical factors.

• Security as the foundation: B2B SaaS applications routinely handle sensitive business data that demands protection. Authentication is the first line of defense against unauthorized access and potential security breaches. For enterprises, compromised authentication can lead to data exposure, compliance violations, and damaged reputation.
• User experience as the enabler: Even the most secure authentication system fails if users find it too cumbersome. When authentication friction becomes excessive, user adoption suffers, productivity decreases, and ultimately, the value of your solution diminishes.

This balancing act becomes particularly crucial in B2B SaaS environments where complex permission structures, various user roles, and strict compliance requirements further complicate the equation. The most successful authentication implementations deliver enterprise-grade security without sacrificing the seamless experience users expect.

SaaS authentication methods

Choosing the right authentication method is essential for SaaS applications because it impacts both security and the user experience.

In this section, we'll explore several SaaS authentication methods, including:

• Traditional password-based authentication
• Passwordless approaches
• Social authentication
• Single Sign-On (SSO)
• Multifactor authentication

Let’s take a look at how each auth method fares when it comes to security and user experience.

Password-based authentication

This traditional method uses a combination of email addresses or usernames and passwords to verify user identities. While it’s the easiest to implement on this list, it's crucial to enhance security by requiring strong passwords, hashing passwords before storage, and implementing multifactor authentication (MFA).

Reasons passwords remain popular:

• Simple to set up on any platform.
• Users are familiar with passwords.
• Cost-effective implementation.

Vulnerabilities:

• Phishing: Tricking users into sharing passwords.
• Credential stuffing: Using stolen passwords on different apps and logins.
• Brute-force attacks: Guessing several combinations of letters and numbers.

Example:

A user creates an account in your project management SaaS application by providing their email address and password. Your application stores the password securely after hashing it. When the user logs in, your application verifies the entered password against the stored hash.

Best practices

• Salting: A unique salt (random string) should be added to each password before hashing to prevent attackers from using precomputed hash tables or “rainbow tables”.
• Use rate-limiting to prevent brute force attacks.
• Prevent users from selecting common passwords such as 12345678—you can often implement rules such as “Password should contain an uppercase letter and a number.”
• Check user passwords against databases like “Have I Been Pwned” to find leaked passwords.

Best for: Smaller organizations, legacy applications, or internal SaaS apps with limited risk exposure.

Social authentication

Social authentication allows users to sign in to your SaaS application using their existing accounts from popular platforms like Google, Facebook, LinkedIn, GitHub, or Twitter.

This method leverages OAuth 2.0, a widely adopted protocol for secure authorization. Social authentication securely delegates authentication to trusted providers without direct credential handling.

How social authentication works:

• Users select their preferred social platform (like Google or GitHub) during the login process.
• They're redirected to that platform, where they authenticate using credentials they already have.
• After successful login, the platform returns an access token to your SaaS application, confirming the user's identity and sharing basic profile details (such as name and email).
• The SaaS application (your app) then authorizes access based on this verification without needing to manage separate credentials.

Benefit: Social authentication leverages the existing security practices of established platforms. This reduces password-related vulnerabilities like phishing or password reuse.

While traditionally associated with B2C, social login is gaining traction in B2B, particularly for platforms where professional identity is relevant.

The choice of which social login to offer should align with the B2B SaaS's function. For example, "Sign in with LinkedIn" makes sense for a corporate event management tool. A devtool would benefit with a GitHub social login.

Enterprise Single sign-on (SSO)

Enterprise SSO enables users to access multiple applications with a single set of credentials. It streamlines the login process, improves user experience, and enhances security by reducing the number of passwords users need to manage.

If you’re a B2B SaaS company looking to get enterprise customers, the enterprise will want your app to support login through their identity provider (IdP like Okta). To do this, you need to implement SSO in your app.

In a B2B SaaS context, Enterprise SSO enables organizations to integrate their IdPs with the SaaS application, streamlining access for employees while maintaining security and compliance.

Here’s how it works:

SSO typically follows SAML (Security Assertion Markup Language) or OIDC (OpenID Connect) protocols. The main components in an SSO setup include:

• Service Provider (SP): The application or system that requires authentication (your B2B SaaS app).
• Identity Provider (IdP): The trusted system that authenticates the user (e.g., Okta, Microsoft Entra ID, Google Workspace).
• User: The employee or customer trying to access the SaaS application.
• Assertion: A package of information (e.g., user identity, roles, permissions) sent from the IdP to the SP.
• Authentication flow: The process of validating the user and granting access.

The typical authentication flow usually goes like this:

• User visits your app (SP). Your app redirects the user to the IdP.
• IdP authenticates the user and generates a SAML assertion and sends it back to your app.
• Your app validates the assertion, creates a new session for the user, and logs them in.

Best for: B2B SaaS apps that are targeting enterprises. Enterprises frequently require SSO for compliance reasons, improved security posture (fewer passwords to manage), and a better user experience for employees who need to access numerous applications.

Passwordless authentication

This approach eliminates the need for passwords altogether, enhancing both security and user experience. Let’s take a look at common passwordless authentication techniques.

Magic links

This method sends unique, time-sensitive login links to the user's email address, allowing passwordless authentication. Magic links are convenient for users as they don’t have to manually key in an OTP.

Best for: Applications with infrequent logins.

Scenario: A user onboarding/training SaaS app sends magic links for occasional users who don't log in frequently.

OTPs

OTPs are passwords that are valid for only one login session or transaction. They can be generated and delivered through various means such as texts or email.

OTPs are temporary codes generated using standards like TOTP (Time-based) or HOTP (event-based). They are typically valid for short durations (30–60 seconds).

Best for: Securing transactions, user onboarding

Example: A user initiates a login or transaction. The system generates a unique OTP and sends it to the user's registered number via text. The user enters the OTP to complete the authentication process.

Passkeys

They are a phishing resistant auth method based on public key cryptography. They are part of the FIDO2 (Fast Identity Online) standard and are supported by companies like Apple, Google, and Microsoft.

When signing up for your SaaS app, a public-private key pair is generated on the user’s device. The public key is stored on the server, while the private key stays securely on the user’s device. When logging in, the service (Your SaaS app) sends a challenge, which the user’s device signs using the private key.

Best for: High-security areas, such as financial services, healthcare, and enterprise-critical applications.

Example: A fintech SaaS platform enables secure logins with passkeys, significantly reducing phishing and credential theft risks.

Multi-factor Authentication (MFA)

Multi-Factor Authentication (MFA) strengthens SaaS authentication by requiring multiple forms of verification instead of relying on just a password. MFA significantly enhances security, as an attacker who has one factor (like a compromised password) cannot gain access without the additional factor(s).

MFA typically combines two or more of the following factors:

• Knowledge factor: Something you know, like passwords or PINs.
• Possession factor: Something you have, such as a mobile device (through which you can receive an OTP).
• Inherence factor: Something you are, for example, your fingerprint.
• Adaptive MFA: Dynamically requests additional authentication based on risk assessment indicators (location, device, login frequency, or unusual behaviors).

For authentication in SaaS applications, a good MFA solution uses a combination of factors that complement each other, balancing security with user convenience.

MFA substantially improves security, particularly against compromised passwords, phishing, or credential theft.

However, each added authentication factor slightly increases user friction. Avoid overly complex combinations unless high-security stakes justify it.

Purchase checklist for SaaS authentication solutions

When selecting an authentication solution for your SaaS application, consider the following:

• B2B vs. B2C authentication: When evaluating SaaS authentication solutions, it’s crucial to understand the nuances between B2B and B2C authentication. B2C applications typically deal with individual users. B2B SaaS, however, must accommodate complex organizational structures, often involving multi-tenancy (multiple organizations using the same application instance) and enhanced security. Keep this in mind when you pick an auth solution—several vendors specialize in B2C authentication.
• SSO and MFA: SSO login is an essential feature for enterprises (your prospects), allowing their users to have a standard and secure login experience. MFA adds an essential security layer against unauthorized access through options like SMS, authenticator apps, or biometrics.
• IdP integration: Ensure that the authentication solution integrates with the IdPs your target customers already use (e.g., Okta, Azure Active Directory, Google Workspace). This will help when your prospects are evaluating you, since they can directly use their IdP to authenticate your app.
• SCIM support: Evaluate if the solution supports System for Cross-domain Identity Management (SCIM) to simplify and automate user provisioning and deprovisioning across your systems.
• Customization: Choose a solution offering customizable authentication flows and fully branded user experiences, including login pages, messages, and domain customization, to maintain consistency with your application's design and branding.
• Centralized admin portal: Select a solution that has an intuitive admin portal. This enables efficient user management, role assignments, policy configurations, and comprehensive audit trails and reporting. This is crucial while dealing with enterprises, where administrative complexity is expected.
• Compliance: Opt for a solution compliant with relevant industry standards (GDPR, CCPA, SOC 2, ISO 27001), offering robust security features like data encryption, regular audits, and clear data policies.
• Pricing: Choose a solution that doesn’t bill you for Monthly Active Users (MAU-based pricing). Also try to avoid providers who gate features—you will end up paying more as you or your customers scale.

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Comparing SaaS authentication providers

Several tools are built for authentication in general, but if you’re a B2B SaaS, you should consider one that is purpose-built for SaaS complexity and environments.

Scalekit

Scalekit is designed specifically for B2B SaaS applications with solutions like SSO, SCIM provisioning, and social logins. It focuses on multi-tenancy and organization-first workflows to simplify enterprise onboarding. It offers a scalable architecture that aligns with enterprise growth needs.

Key features:

• Single Sign-On (SSO) via OIDC/SAML
• SCIM provisioning for automated user management
• Social logins integration
• With a centralized admin portal, your customers’ IT teams can configure SSO, SCIM, and user attributes independently. This means your team spends less time spent going back and forth with your customers’ IT teams.
• Seamless integration with major IDPs like Okta, Microsoft Entra ID, and Google SAML
• Developer-friendly SDKs and APIs for rapid integration
• Free for the first three SSO or SCIM connections. No MAU charges or hidden fees. Unlimited social logins included.

Auth0

A comprehensive identity management platform offering a wide range of authentication and authorization services for B2C and B2B applications. A customizable solution for securing applications.

Key features:

• Universal login
• SSO
• MFA
• Support for various identity providers
• Machine to machine authentication

Compare Auth0 alternatives

WorkOS

WorkOS provides a suite of features that lets SaaS team get enterprise-ready, including SSO and directory sync, to help applications integrate easily with enterprise systems.

Key features:

• Enterprise SSO (SAML, OpenID Connect)
• Directory sync (SCIM)
• Fine-Grained Authorization (FGA)
• Admin portal
• Audit logs
• Developer-friendly APIs and SDKs

Compare WorkOS alernatives

Descope

A modern, no-code/low-code authentication platform designed for mid-market and enterprise business to simplify all-round authentication and user management. It offers pre-built UI components and workflows for quick and easy implementation.

Key features:

• Drag-and-drop flow builder
• Passwordless authentication methods
• Pre-built UI components
• Social login
• Risk-based authentication

Clerk

Clerk is an authentication platform that offers developers pre-built tools for login, signup, and profile management. It features ready-to-use UI components, APIs, and support for flows like SSO, MFA, and Social Logins, along with SDKs, database integrations, and customization options.

Key features:

• Embeddable UI components (sign-in, sign-up, user profiles)
• MFA
• Passwordless authentication
• Social login
• Session management
• Role-based access control

Frontegg

Frontegg is an authentication and user management platform tailored for B2B SaaS applications. It supports a multi-tenant architecture with organization-level settings and features like fine-grained authorization, API token management, and SSO via SAML and OIDC. The platform covers the entire user journey, from signup to subscription enforcement.

Key features:

• Multi-tenancy support
• Role-based access control (RBAC)
• Organization and user management
• SSO, SCIM
• Subscription management integration

Stytch

Focuses on providing modern, passwordless authentication solutions with an emphasis on security and user experience. It offers a flexible API for integrating various passwordless methods into applications.

Key features:

• Embeddable admin portal
• Machine-to-machine authentication
• Passwordless authentication (Magic links, OTP, Biometrics)
• One-tap Login
• Social login
• Flexible API for customization

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Final thoughts

Choosing the right authentication solution is a critical decision for any SaaS business.

The ideal solution should strike a balance between strong security, scalability, user experience, and ease of integration. Explore third-party authentication platforms to accelerate your time-to-market without taking time away from your engineering team.

A well-implemented authentication system is not just a security feature; it's a strategic lever that builds trust, enhances user satisfaction, and drives business growth.