Category: Customer Identity

B2B Identity

Also known as: B2B IAM, Business-to-Business Identity and Access Management, B2B Identity Management, B2B CIAM

Simply put

B2B identity is the set of processes and technologies an organization uses to confirm the identities of external users and the partner organizations they belong to, then manage what those users can access. It focuses on people from other businesses, such as clients, suppliers, distributors, and resellers, rather than an organization's own employees. The goal is to let a company's workforce and its business partners collaborate securely across shared applications and services.

Formal definition

B2B Identity (B2B IAM) refers to identity and access management tailored to external organizations and their users, partners, clients, suppliers, distributors, resellers, and guests, as distinct from internal workforce identities. It typically addresses both the authentication of external users and the modeling of the organizations they belong to, so that access to applications and services can be provisioned and governed at an organizational level in addition to the individual-user level. In practice, deployments vary: some vendors frame B2B collaboration as enabling a workforce to work securely with external partners and guests (for example, Microsoft Entra External ID's B2B collaboration), while others position B2B CIAM as managing how business partners authenticate and collaborate. The evidence provided does not specify particular protocols, federation profiles, or standards, so those details are out of scope for this definition.

Why it matters

Organizations increasingly depend on external collaboration, clients, suppliers, distributors, resellers, and guests all need access to shared applications and services. B2B identity matters because these external users are not part of an organization's own workforce, yet they still require reliable identification, authentication, and appropriately scoped authorization. Treating partner users the same as employees, or bolting them onto workforce identity systems without accounting for the organizations they belong to, tends to create both security gaps and operational friction.

A defining challenge of B2B identity is that access often needs to be reasoned about at two levels: the individual external user and the partner organization that user belongs to. In most deployments, this organizational dimension is what distinguishes B2B identity from ordinary consumer or workforce scenarios, because provisioning, access decisions, and governance may need to apply to a whole partner entity in addition to specific people. Getting this modeling wrong can lead to over-broad access, orphaned partner accounts, or difficulty revoking access when a business relationship ends.

Vendor approaches vary in how they frame the problem, which affects how organizations plan their deployments. Some position it as enabling an internal workforce to collaborate securely with external partners and guests, Microsoft Entra External ID describes its B2B collaboration capabilities in these terms. Others frame B2B CIAM around how business partners themselves authenticate and collaborate. Because these framings emphasize different sides of the relationship, evaluating a solution requires clarity about whose users and whose applications are being governed.

Who it's relevant to

IAM and Identity Architects

Architects designing external-facing access must model both individual partner users and the organizations they belong to, keeping this distinct from internal workforce identity. They decide how partner collaboration is structured across shared applications and services, and how access is scoped and governed at the organizational level.

Identity Governance Leads

Because B2B access is tied to business relationships, governance leads are concerned with provisioning and de-provisioning partner access as relationships begin and end. Managing access at the partner-organization level, in addition to the individual level, is central to preventing orphaned or over-broad external access.

System Administrators

Administrators operate the platforms that let a workforce collaborate with external partners and guests, and that manage how those external users access applications and services. Their day-to-day concerns include onboarding partner organizations and their users and maintaining appropriate access over time.

Compliance Officers

Compliance stakeholders care that external users from partner organizations are properly identified, authenticated, and authorized, and that access can be attributed to the correct business partner. The organizational dimension of B2B identity supports demonstrating who, and which partner, had access to what.

Inside B2B IAM

Organization or tenant modeling

The representation of external partner, customer, or supplier organizations as distinct entities within the identity system, typically so that users can be grouped, administered, and authorized in the context of the organization they belong to rather than solely as isolated individuals.

Federated authentication with partner IdPs

Support for delegating authentication to a partner organization's own identity provider, commonly via SAML 2.0 for web SSO or OpenID Connect (built on OAuth 2.0). This lets external users authenticate against their home directory while the relying application consumes the resulting assertion or ID token.

External user lifecycle and provisioning

IGA-oriented processes for onboarding, updating, and deprovisioning partner users, often using SCIM for automated provisioning or invitation/self-service flows. This is a lifecycle-management concern distinct from runtime access enforcement.

Delegated administration

Capabilities that allow a partner organization to manage its own users and their access, such as inviting members or assigning roles within that organization's scope, typically without granting control over other tenants.

Cross-organization authorization

Determining what an external principal may do, frequently expressed through access control models such as RBAC (roles scoped to an organization), ABAC (attributes including organization membership), or ReBAC (relationship-based access between users and organizations). The applicable model depends on the deployment.

Token and claim propagation

Conveying organization or tenant context in tokens and assertions, for example organization identifiers as claims within a JWT ID token or in a SAML assertion, so downstream services can enforce tenant-aware authorization. Note that a signed token is not the same as an encrypted one.

Common questions

Answers to the questions practitioners most commonly ask about B2B IAM.

Is B2B identity just the same as B2C identity applied to business users?

No. While both are external identity use cases, B2B identity typically centers on organizations (tenants, partner companies) as the primary unit rather than individual consumers. In most B2B deployments you manage relationships between your organization and partner organizations, often delegating user administration to the partner and federating with the partner's existing identity provider. B2C flows, by contrast, usually treat each user as a self-registering, self-managed individual. The data models, delegated administration, and federation expectations differ significantly depending on your deployment.

Does federating with a partner mean I am authenticating their users myself?

Not directly. In a typical B2B federation, the partner organization's identity provider performs the authentication of its own users, and your system consumes an assertion or token as evidence of that authentication. For example, using SAML 2.0 or OpenID Connect, you rely on the partner IdP to verify who the user is (authentication), while your side is responsible for determining what that authenticated principal may do (authorization). Conflating these steps is a common error: identification, authentication, and authorization remain distinct even when authentication is delegated.

How do I model partner organizations and their users in a B2B system?

A common approach is a multi-tenant model where each partner organization is represented as a tenant with its own set of users, and cross-tenant relationships are expressed explicitly. Some deployments use ReBAC (relationship-based access control) to represent organization-to-user and organization-to-resource relationships, while others layer RBAC roles scoped per tenant. The right model depends on how much isolation, delegated administration, and cross-organization access your use case requires; there is no universally superior choice.

How should I handle provisioning and deprovisioning of partner users?

This is an identity governance and administration (IGA) concern distinct from runtime enforcement. In many B2B deployments, provisioning is either delegated to the partner's own administrators or automated via SCIM where the partner's system pushes lifecycle events. Where federation is used, some organizations rely on just-in-time provisioning at first login and pair it with periodic access reviews and certification. Deprovisioning is often the harder problem, since a user offboarded at the partner may not be immediately reflected on your side depending on configuration; timely signals such as SCIM deprovisioning or short token lifetimes help mitigate this.

How do I delegate administration to partner organizations safely?

Delegated administration typically means granting designated partner administrators the ability to manage their own organization's users and role assignments without giving them access to other tenants or your internal administration. This is usually implemented by scoping administrative permissions to a tenant boundary and constraining which roles a partner admin can assign. Pairing delegation with segregation of duties controls and periodic access certification, both IGA functions, helps prevent privilege accumulation. The exact capabilities available depend on your platform and configuration.

What authorization approach works when partners have different access needs per resource?

When access requirements vary across partners and resources, many deployments move beyond static roles toward ABAC (attribute-based) or PBAC (policy-based) models, evaluating attributes such as partner organization, contract tier, or resource sensitivity at runtime. Architecturally this often separates a policy decision point (PDP) from the policy enforcement point (PEP), with a policy information point (PIP) supplying partner and user attributes. The appropriate model depends on the granularity and dynamism your scenarios require; RBAC scoped per tenant may still suffice for simpler cases.

Common misconceptions

B2B identity is just B2C identity with a company name attached.

B2B identity typically centers on the organization as a first-class entity, with federation to partner IdPs, delegated administration, and tenant-scoped authorization. These organizational and governance concerns differ substantially from consumer-facing individual identity flows.

Federating with a partner's identity provider handles authorization for external users.

Federation addresses authentication, verifying who the external user is via the partner IdP. Determining what that user may do is a separate authorization step, usually enforced by the relying application or service using models such as RBAC, ABAC, or ReBAC, and often scoped to the user's organization.

Once a partner user is provisioned, access management is complete.

Provisioning is an IGA lifecycle activity, not runtime enforcement. Deprovisioning, periodic access reviews, and certification remain necessary, and every request still requires runtime authorization decisions and token validation independent of the initial onboarding.

Best practices

Model external partners as distinct organizations or tenants so that users, roles, and access can be scoped and administered within their organizational context rather than as flat individual accounts.

Use standards-based federation, SAML 2.0 or OpenID Connect, to delegate authentication to partner IdPs where appropriate, and keep authorization decisions separate from the authentication assertion.

Automate external user lifecycle with SCIM-based provisioning or controlled invitation flows, and ensure deprovisioning is equally reliable so departed partner users lose access promptly.

Implement delegated administration to let partner organizations manage their own users within a bounded scope, without granting cross-tenant control.

Choose an authorization model (RBAC, ABAC, or ReBAC) that fits the deployment and consistently include organization or tenant context in enforcement decisions and token claims.

Conduct periodic access reviews and certification of external identities as an ongoing IGA control, distinct from runtime token validation, to limit standing access accumulation.