What It Is
M365 architecture is the set of structural decisions that determine how an organization's Microsoft 365 environment is organized, governed, and operated. This includes tenant design, Exchange Online mail flow and configuration, Teams governance and information architecture, SharePoint site structure and permissions design, OneDrive governance, licensing strategy, and the integration of security and compliance workloads across all of it. Architecture decisions made at tenant setup have long-tail consequences that are expensive to reverse. Getting them right early saves significant remediation cost later.
Why It Matters
Most M365 environments accumulate technical debt quietly. Teams proliferate without governance. SharePoint permissions sprawl. Guest access grows unchecked. Licensing is assigned broadly rather than by role. None of these problems announce themselves. They compound slowly until an audit finding, a security incident, or a Copilot deployment surfaces them all at once. Good M365 architecture addresses these structurally rather than reactively, with governance built into the platform configuration rather than enforced through manual processes that degrade over time.
Architecture Scope
- Tenant design - Single vs. multi-tenant decisions, tenant configuration standards, domain structure
- Exchange Online - Mail flow, transport rules, retention policies, shared mailbox governance
- Microsoft Teams - Provisioning governance, naming conventions, lifecycle management, external access controls
- SharePoint and OneDrive - Site architecture, permissions design, sharing policies, external collaboration controls
- Licensing architecture - Role-based license assignment, utilization review, cost optimization
- M&A integration - Tenant consolidation, cross-tenant migration, identity boundary decisions
In Practice
At NBT, I was the principal architect for M365 environments across approximately 25 client tenants, responsible for platform design, configuration standards, governance frameworks, and security baselines across all of them. The scale meant developing architectural patterns that could be applied consistently while still being adapted to each organization's specific requirements, licensing posture, and compliance needs.
M365 architecture has been the core of my work for the past several years. At NBT, I was the principal architect for M365 environments across approximately 25 client tenants, responsible for the platform design, configuration standards, governance frameworks, and security baselines across all of them. The scale of that work meant developing architectural patterns that could be applied consistently while still being adapted to each organization's specific requirements.
There were three potential acquisitions at Latham Pool Products, one of which was completed. It was a small organization. The work involved planning meetings and coordination around how integration would be approached, contributing to the thinking about tenant boundaries and identity decisions.
At cb20 Technology Solutions, Latham Pool Products was my primary engagement but the MSP context meant understanding M365 architecture across a wider range of organization types and sizes. What works at 1,000 users does not automatically scale to 10,000, and what is appropriate for a manufacturing company does not translate directly to a financial services firm. Architectural pattern recognition across environments is one of the things MSP work develops that single-organization roles do not.
- 25-tenant M365 platform architecture - Principal architect for M365 environments across approximately 25 NBT client tenants. Owned platform design, configuration standards, governance frameworks, security baselines, and licensing strategy across the full client portfolio.
- M&A planning for three potential acquisitions - Participated in integration planning at Latham Pool Products. One acquisition was completed, a small organization. Contributed to planning and coordination work around the integration approach.
- E5 capability activation program - Led the systematic activation of M365 E5 capabilities across client environments at NBT and specifically at Latham Pool Products, identifying capabilities included in existing licenses that had not been deployed and building the business case and implementation plan for each.
- Teams governance framework design - Designed Teams provisioning governance frameworks including naming conventions, lifecycle management policies, external access controls, and meeting policy standards - reducing Teams proliferation and the guest access sprawl that tends to follow unmanaged deployments.
- Exchange Online architecture and migration - Designed and executed Exchange Online configurations including mail flow rules, transport configuration, retention policy frameworks, and shared mailbox governance across multiple client environments.
- License utilization optimization - Conducted systematic license utilization reviews identifying E5 capabilities paid for but not activated, redundant third-party tools that native M365 capabilities could replace, and mis-assigned license tiers - recovering material licensing cost in multiple engagements.