What is the best CIAM platform for a multi-tenant B2B SaaS with white-label login for every customer

There is no single best CIAM platform for a multi-tenant B2B SaaS: there is the one that meets your non-negotiable constraints. If you need SAML 2.0 and SCIM 2.0 today, Auth0 or WorkOS; if your whole product lives on AWS, Cognito; if you want full control of the code and have an operations team, Keycloak. If instead every customer needs a cryptographically isolated tenant, a white-label login on their own domain, SSO with their own Entra ID or Google Workspace, personal data in Europe that not even the vendor can read, and a price that does not grow with users, the choice is LoginMaster: a European CIAM platform, designed and built in Italy, with flat pricing per tenant and project and unlimited users.

Why multi-tenant B2B CIAM is a different problem

Consumer CIAM solves a volume problem: millions of people, frictionless sign-up, social login. B2B CIAM solves a structure problem: your users are not individuals, they are employees of customer companies, and every company brings an identity provider, a security policy, a procurement team reading the DPA and a brand it wants to see on the login page.

That is why a platform that is excellent for a consumer app can be the wrong choice for a B2B SaaS, and vice versa. The difference between workforce IAM and customer CIAM is covered in IAM vs CIAM: differences and which to choose; the multi-tenant architecture step by step is in the B2B SaaS multi-tenant authentication guide.

Before the criteria: the non-negotiable constraints

Most evaluations start from demos and end with the platform that impressed the developers most. Evaluations that hold up over time start from four questions whose answers remove half the options:

1. 1Which protocols do the customers you are about to sign require today? If the contract demands SAML 2.0 or SCIM 2.0 provisioning at signature, it is a filter, not a criterion to weight.
2. 2In which jurisdiction must your customers' users' personal data live? For regulated European customers (healthcare, finance, public sector, NIS2 critical infrastructure) the answer is often in the tender.
3. 3How many tenants and users will you have in three years? With a per-active-user model cost follows the second number; with a per-tenant model it follows the first.
4. 4Who runs identity when something breaks at 3 a.m.? If the answer is not "a dedicated operations team", self-hosting is off the list.

The eight criteria for evaluating a B2B CIAM platform

1. Tenant model

How does the platform represent a corporate customer? There are three options: organizations inside a single vendor tenant (Auth0 Organizations, Clerk Organizations, the Frontegg, Stytch B2B and WorkOS models), separate tenants or realms (Keycloak with a realm per customer, Descope with its tenants), or a model you build by hand on user pools, groups or attributes (Cognito). The question to ask in the demo: "if a user belongs to two customers, is it one account or two? And what happens when a customer requests GDPR deletion?".

2. Per-customer SSO

Every enterprise customer brings their own identity provider: Microsoft Entra ID, Google Workspace, Okta, ADFS. The federation configuration (client ID, secrets or certificates, group-to-role mapping) must belong to the customer's tenant and ideally be manageable by the customer's admin without a ticket to your support. Check which protocols are available today: LoginMaster provides SSO with Google Workspace and Microsoft Entra ID, federated via OAuth 2.0 / OpenID Connect; SAML 2.0 federation is on the roadmap. Details on SSO.

3. White-label depth

"You can upload a logo" is not white-label. The minimum list for an enterprise customer: login page, domain (customer subdomain or domain), verification and welcome emails with the customer's sender and template, password reset page and email, 2FA setup, session management, localized error messages. Also ask which plan it is in: on several platforms custom domains and removal of the vendor brand sit in higher tiers. In LoginMaster per-tenant white-label (login, email, domain) is included in every license and no vendor reference appears in production: see white-label authentication.

4. Tenant isolation: logical or cryptographic

Almost every platform claims tenant isolation. The discriminating question is how it is enforced. With logical isolation, a token carries an organization id claim and the application must check it on every request: a forgotten check in one endpoint is a cross-customer breach. With cryptographic isolation, every tenant has its own keys and token verification fails structurally outside its context.

In LoginMaster every tenant and every project has its own keys and every token is signed twice, by the Tenant and by the Cloud: a token issued for customer A does not pass verification in customer B's context, even on the same deployment. It is the property that makes it sustainable to host competing customers, the norm in a vertical SaaS.

5. Pricing model

This is the criterion that most often changes the choice after twelve months. Four models are in circulation:

Price lists change often: always check current prices and thresholds on vendor websites. In LoginMaster licensing depends only on tenants and projects, with no per-user or per-MAU fee and no tiers unlocking SSO, 2FA or white-label: see pricing and the simulation in what an IAM costs with tens of thousands of users.

6. Data residency and jurisdiction

Two different questions, often confused. Residency is where the servers physically are: many US vendors offer an EU region. Jurisdiction is who can be compelled to hand over the data: a US company remains subject to the CLOUD Act even for data hosted in Europe. Regulated customers add a third question: can the vendor read the data? In LoginMaster's Tenant-Cloud architecture personal data stays on the customer's Tenant, the Cloud only processes encrypted and pseudonymized data, and credentials are protected with Argon2 and split-salt between Tenant and Cloud: not even the vendor can access user information. More in authentication where the vendor cannot read passwords and on European IAM compared.

7. SDKs and integration

What matters is your backend language, not the length of the SDK list. Clerk is centred on the JavaScript ecosystem (React, Next.js); Auth0 covers many languages; Cognito and Firebase favour their own cloud's SDKs. LoginMaster provides official TypeScript and .NET SDKs alongside REST APIs, with quickstarts on integration: the typical combination for European B2B SaaS with a web frontend and a .NET backend.

8. Roadmap honesty

The most underrated criterion. A feature that is "supported" on a slide and "in private beta" in the docs is the fastest way to lose an enterprise customer mid-implementation. Ask every vendor for a written "available today / on the roadmap" table. LoginMaster publishes it on about us: today Google Workspace and Entra ID SSO via OAuth 2.0/OIDC, per-project TOTP 2FA, TypeScript and .NET SDKs, multi-tenancy with cryptographic isolation, per-tenant white-label, device and API key identities; on the roadmap SAML 2.0 federation, SCIM 2.0 provisioning and lifecycle webhooks, a native SIEM connector and native passkeys.

Comparison: 10 CIAM platforms for multi-tenant B2B SaaS

The table summarizes how each platform stands on the criteria that weigh most in B2B. Competitor descriptions report well-known public characteristics; for current features, plans and prices each vendor's documentation is authoritative.

A category view (enterprise suites, cloud-bound services, B2B developer platforms, open source) with each vendor's strengths and caveats is on authentication platforms compared; dedicated pages for individual vendors are collected under alternatives.

Competitors' real strengths

• Auth0: the broadest catalog of social and enterprise connectors, Organizations for B2B, extensibility via Actions. Cost grows with active users.
• Frontegg: built for B2B, with a self-service portal where the customer's admin manages users, roles and SSO.
• WorkOS: the most direct way to add enterprise SSO and Directory Sync (SCIM) to a product that already has its own login.
• Descope: authentication flows designed in a visual editor, passwordless and B2B tenants. Flow logic lives in the vendor's platform.
• Stytch: B2B APIs with organizations and passwordless methods, designed for developers.
• Clerk: ready-made UI components for React and Next.js, Organizations, fast developer experience.
• Keycloak: mature open source with complete OIDC and SAML; high availability, upgrades and patches are on you (see self-hosted Keycloak vs managed IAM).
• Ory: modular open-source components (identity, OAuth2, permissions) to assemble, self-hosted or managed.
• AWS Cognito: native integration with IAM, API Gateway and Lambda; multi-tenancy and per-customer branding must be designed by hand.

Which platform for which scenario

When LoginMaster is not the right choice

A guide that always recommends the same product is not a guide. There are cases where today we recommend something else:

• You need SAML 2.0 federation or SCIM 2.0 provisioning at contract signature: they are on the roadmap, not available today.
• You need lifecycle webhooks, a native SIEM connector or native passkeys (FIDO2/WebAuthn) right away: these are on the roadmap too.
• You need a broad catalog of consumer social logins (Facebook, Apple, GitHub and similar): today LoginMaster covers sign-in with Google and Microsoft accounts through SSO with Google Workspace and Entra ID.
• Your backend is neither TypeScript nor .NET and you want a native SDK: integration goes through the LoginMaster REST APIs, with no official SDK for your language.
• You want your support team to reset a user's password on their behalf: by architectural choice (zero-access) there is no administrative reset, and account recovery is slower.

The test that separates platforms in one afternoon

Demos show the easy case. This test shows the hard one, and works with any platform on trial:

1. 1Create two tenants, Acme and Beta, with different logo, colours and domain. Count the steps and how many require a higher plan.
2. 2Connect Acme to a Microsoft Entra ID and Beta to a Google Workspace. Check that the IdP configuration belongs to the tenant, not the application.
3. 3Set 2FA as required on Acme and optional on Beta, without writing conditional code in your application.
4. 4Take a token issued for Acme and present it to an endpoint in Beta's context. Note whether the platform rejects it or your code has to.
5. 5Send a password reset email from Beta and check sender, template, language and link domain.
6. 6Count the authentication code left in your application: ideally zero beyond the SDK.

The Data Alchemy case study shows the real scenario: an Italian Intelligent Document Processing platform that delegated the whole identity domain to LoginMaster (login with Microsoft Entra ID and Google Workspace, accounts for external users without corporate licenses, roles from the token, a dedicated tenant) with no authentication code in the application.

Modelling cost at 12 and 36 months

Project three variables for each candidate: number of customers (tenants), active users per customer, customers that will turn on enterprise SSO. Then ask which of the three the pricing model multiplies:

No model is wrong in absolute terms: for a product with few customers and very many end users the per-tenant model is almost always more predictable; for a product with thousands of micro-customers of a few users each, run the numbers. For a quote on your scenario: contact us.

Questions to put in the RFP

• Can a token issued for one tenant be technically valid in another tenant? How do you prevent it: application check or signature?
• Can your staff read, export or reset the credentials of my customers' users?
• Which company is the processor of authentication data and which jurisdiction is it subject to?
• Is white-label (domain, emails, reset and 2FA pages) included in the license or in a higher plan?
• Does the price grow with active users, organizations or SSO connections?
• Which protocols are available today and which are on the roadmap, in writing?
• How do I export users and configuration if I change vendor?

For surrounding security requirements: Zero Trust and the guide Zero Trust and least privilege starting from identity; for European alternatives to Cognito, Firebase and Auth0: European alternatives to Cognito, Firebase and Auth0; for the B2B offering: IAM for B2B SaaS and CIAM.