B2B portals with SharePoint: connect suppliers and customers securely

ICT 365 builds B2B portals on SharePoint Online and Microsoft Entra: supplier and customer portals with guest accounts, onboarding processes, role-based dashboards and secure document exchange. Your partners work with you on a controlled platform instead of email attachments – proven by the partner portal for ArcelorMittal Hamburg GmbH with more than 50 connected partners.

Illustration: a portal connects two companies through a protected platform with documents and cloud

When partner data travels the world as email attachments

Collaboration with suppliers and customers rarely fails for lack of will – it fails on tools designed for internal teams only. Typical situations:

Quotes, drawings and orders go back and forth as email attachments – without version control.
External users get VPN access or shared accounts because clean guest access is missing.
Onboarding a new supplier takes weeks and runs on forms, phone calls and shoulder taps.
Nobody can prove which partner received which documents, and when.

What our portal development covers

From the first role concept to day-to-day operation, everything comes from one partner:

Portal structure, roles and permission model
Onboarding processes with invitation, intake form, review and approval
Guest accounts with Microsoft Entra ID, with third-party identity providers where wanted
Personalised dashboards and branded interfaces with SharePoint and React
Automated provisioning, task tracking and escalations with Power Automate
Operation, lifecycle of external accounts and further development after go-live

An extranet on SharePoint: why you don't need a separate portal product

The key architecture question: a dedicated portal product – or what your Microsoft 365 tenant can already do?

We build portals as a SharePoint extranet: external users work with guest accounts in Microsoft Entra ID – with multi-factor sign-in, individual permissions and a central lifecycle, without extra infrastructure and without licence costs for a separate portal product. Custom interfaces are built with SPFx and React, the processes behind them with Power Automate. The portal stays part of your existing security and governance landscape – rules such as Conditional Access apply to externals too.

Diagram: internal Microsoft 365, portal layer with guest access and external partners, connected through secured paths

Security and control for external collaboration

A portal is only as good as the control over who sees what.

That is why every portal project includes a clean permission model, traceable approvals and a lifecycle for external accounts – from onboarding to automatic deactivation. Permissions stay reviewable, access is logged. This is also the precondition for safely introducing AI features such as Microsoft 365 Copilot later: what externals must not see, no Copilot may find either.

Proven in practice

ArcelorMittal: partner portal for buyers and suppliers

For ArcelorMittal Hamburg GmbH we rebuilt supplier collaboration – a SharePoint-based portal connects buyers and suppliers and makes the exchange of documents and information secure.

Onboarding with invitation, intake form, review and approval
Automatic SharePoint provisioning and a personalised dashboard per supplier
Guest accounts in Microsoft Entra ID, escalation system for supplier tasks
More than 50 connected partners with 200 to 300 users

How your B2B portal takes shape with ICT 365

Initial conversation and goals

We understand which partners you work with, which processes the portal should carry and where things stall today.
Concept: roles, processes, permissions

Portal structure, onboarding flow and permission model – as a concept with a reliable effort estimate.
Prototype and iterative development

An early prototype shows dashboard and flows; from there the portal grows in short iterations.
Pilot with first partners

Selected partners work in the portal for real, their feedback flows straight in – then comes the wider rollout.
Operation and lifecycle

Support, monitoring and the management of external accounts across their whole lifecycle.

Frequently asked questions about B2B portals

How much does a B2B portal with SharePoint cost?

It depends on the scope: the number of processes, the complexity of onboarding and the degree of customisation drive the effort. After the concept phase you receive a reliable estimate. There are no running licence costs for a separate portal product – the portal runs in your Microsoft 365 tenant.

How long does it take to build a portal?

A focused portal with a clear onboarding process goes live much faster than a platform with many integrated processes – an honest answer follows the concept phase. Thanks to prototype and pilot, first partners work in the portal early, before everything is finished.

Do our partners need their own Microsoft licences?

Usually no: external users work through guest accounts in Microsoft Entra ID, and sharing SharePoint content with guests is part of Microsoft 365. Whether your scenario has special cases is something we check in the concept phase – you do not have to buy licences for every partner.

How secure is access for external users?

Guest accounts are subject to the same mechanisms as internal ones: multi-factor sign-in, Conditional Access, individual permissions and logging. On top comes a lifecycle process that detects and deactivates unused accounts – control is part of the concept, not an accessory.

Can partners sign in with their own company accounts?

Yes. Besides classic guest invitations, third-party identity providers can be connected so partners use their existing company logins. That lowers onboarding hurdles and avoids password sprawl on the partner side.

Can our ERP or merchandise management system be connected?

Yes – via connectors, APIs and Azure services we integrate existing systems, for example for order or supplier master data. The key is to clarify early which system leads; integrations like these are part of our standard scope.