Enterprise Architecture

The practice, principles and governance model that ties every other reference domain on this site together — not a separate concern from the platform, but the discipline that keeps it coherent.

Principles

Eight principles the practice is built on

These principles apply above and across every domain — they are what the Architecture Review Board checks a decision against, not aspirational values on a poster.

Business-aligned

Every architecture decision traces back to a business outcome, not a technology preference.

Standards-based

Reference models and patterns are reused across the estate instead of reinvented per project.

Reuse before build

Existing platform capability is evaluated before any new component is commissioned.

Evidence-based decisions

Trade-offs are documented and justified — architecture decision records, not tribal knowledge.

Fit-for-purpose

Solutions are sized to the problem; gold-plating and premature scale are both treated as defects.

Transparent trade-offs

Constraints and compromises are stated explicitly, not discovered during delivery.

Federated ownership

Domain teams own delivery; enterprise architecture owns coherence, standards and guardrails.

Continuous evolution

The architecture practice — and the estate it governs — is expected to change, not freeze at a point in time.

Structure

Four TOGAF-aligned domains

Business, Data, Application and Technology Architecture each own a slice of the estate; Enterprise Architecture owns the coherence between them.

Governance

How decisions actually get made

Four governance mechanisms turn the principles above into practice, in the same principle / decision / implementation / guardrail / example format used across this site.

Architecture Review Board

Principle: Significant architecture decisions get independent scrutiny before commitment.
Decision: A standing board reviews and approves solution architectures at the Approve gate of the application lifecycle.
Implementation: Fortnightly ARB session; async approval for low-risk changes via a lightweight decision record.
Guardrail: No production landing zone or platform change proceeds without a recorded ARB or delegated decision.
Example: Contoso's ERP landing zone design was reviewed by the ARB before the first production workload moved in.

Principles & standards catalogue

Principle: Principles are written down, versioned and applied consistently — not reinterpreted per project.
Decision: A single published principles catalogue governs every reference domain on this site.
Implementation: Principles catalogue maintained as versioned content, reviewed annually or on material platform change.
Guardrail: New architecture decision records must reference which principle they satisfy or knowingly deviate from.
Example: The 'Private-by-default' platform principle traces directly to a specific Azure Policy assignment.

Architecture decision records

Principle: Why a decision was made matters as much as what was decided.
Decision: Material architecture decisions are captured as short, structured records — not buried in meeting notes.
Implementation: ADRs stored alongside the solution architecture, referenced from the Architect lifecycle stage.
Guardrail: ADRs are immutable once accepted; changed decisions get a new record that supersedes the old one.
Example: An ADR documents why Service Bus Topics were chosen over Event Grid for the order-fulfilment event.

Reference models

Principle: Common problems get a common answer, published once and reused everywhere.
Decision: Landing zone, integration and identity reference models are maintained centrally and versioned.
Implementation: Reference models published on this site and consumed by delivery teams at the Architect stage.
Guardrail: Deviation from a reference model requires an ADR and ARB sign-off, not silent divergence.
Example: Every landing zone in Contoso's estate inherits the same management group and policy reference model.

In practice

Where this shows up elsewhere on this site

Enterprise Architecture isn't a standalone deliverable — it's the reasoning underneath every other reference domain here.

AI Adoption

Governance-first adoption model, evaluated at the ARB before scale-out.

Azure Landing Zone

The Technology Architecture domain's platform foundation.

Cloud Architecture

Reference patterns for integration, drawn from the standards catalogue.

Application Lifecycle

The gated process that puts EA governance into practice, project by project.

Identity & Access

The Technology Architecture domain's identity and access foundation.