Architecture Registry

Beyond Document Storage

Here's what typically happens when organisations try to create an architecture repository: they set up a SharePoint site, create some folders for different document types, upload a bunch of architecture diagrams and standards documents, and call it done.

Six months later, nobody uses it. The documents are outdated. Nobody knows what's current. Teams can't find what they need. The "architecture repository" becomes another documentation graveyard.

The problem isn't the tool or the folder structure. The problem is treating architecture as a collection of documents rather than a model of interconnected entities. Documents describe things. A registry models things — and the relationships between them.

A proper Architecture Registry isn't a document library. It's a structured representation of your architectural landscape: what exists, how it connects, what governs it, and where it's heading. It's the kind of thing you'd manage in tools like LeanIX, Ardoq, or Orbus iServer — though you can start simpler than that.

What the Registry Models

The registry models entities and relationships across multiple architectural layers. These aren't just documents — they're structured data that can be queried, visualised, and analysed.

The Core Metamodel

At minimum, a useful registry will model:

The power isn't in each layer separately — it's in the relationships between them. Which applications support which capabilities? What data flows between which systems? What technology underpins which applications? These relationships are what transform a list of things into an architecture

Business Architecture in the Registry

Business capabilities describe what the organisation does, independent of how it's done. They're stable over time even as the systems that support them change.

The capability model becomes the bridge between business strategy and technology investment. "We're investing in Customer Experience" translates to specific capabilities, which map to specific applications, which reveals gaps and investment needs.

Value Streams

Value streams show how the organisation creates value — the end-to-end flow of activities that deliver outcomes.

Value streams connect strategy to operations. They show where value is created and where friction exists.

Organisation Model

The registry tracks organisational structure as it relates to architecture:

This enables questions like: "Which teams are affected by this platform change?" or "Who owns the systems supporting this capability?".

Application Portfolio

The application layer is typically the heart of the registry — the inventory of systems that deliver business capability.

Application Inventory

Every application in your landscape should be registered:

Business Alignment:

Technical Profile:

Lifecycle & Health:

Governance:

Application Assessments

Beyond static attributes, the registry can track assessments:

These assessments drive portfolio rationalisation decisions.

Integration & Dependencies

Understanding how things connect is often more valuable than understanding the things themselves.

Integration Inventory

Interface Catalogue

APIs and interfaces exposed or consumed:

Dependency Mapping

The registry should answer:

• Upstream dependencies: What does Application X depend on?
• Downstream dependencies: What depends on Application X?
• Transitive dependencies: If A depends on B and B depends on C, A has a transitive dependency on C
• Critical paths: Which dependency chains are most critical?

This is where EA tools really shine. Visualising a dependency graph across hundreds of applications is nearly impossible in documents or spreadsheets.

Data Flows

Beyond point-to-point integrations, track how data flows through the landscape:

Data Architecture

The data layer tracks how data is structured, stored, governed, and flows.

Data Entities

Logical data entities (often called "business objects" or "data subjects"):

Master Data Sources

For each data entity, which system is the "source of truth"?

Data Stores

Physical data storage:

Technology Landscape

The technology layer tracks platforms, products, standards, and infrastructure.

Technology Catalogue

Every technology in use should be catalogued:

Technology Radar

The radar positions technologies by recommendation:

Platform Inventory

Platforms that applications run on:

Standards

Technology standards in force:

Reference Architectures

Reference architectures provide target state guidance — how things should be built.

Enterprise Reference Architecture

Domain Reference Architectures

More specific reference architectures for particular domains:

• Integration reference architecture
• Security reference architecture
• Data platform reference architecture
• Cloud landing zone architecture
• Identity and access architecture

Each follows similar structure to the enterprise reference, scoped to its domain.

Architecture Patterns

Reusable solutions to common problems:

Building Blocks

Reusable components at different levels of abstraction:

Roadmaps and Transitions

The registry doesn't just model current state — it models target state and the transitions between them.

Current vs Target State

For key entities (applications, capabilities, technologies), track:

Architecture Roadmap

Transition Architectures

For complex transformations, intermediate states:

Views and Visualisations

Raw data isn't useful without ways to see and analyse it. The registry should support multiple views:

Standard Views

Capability-to-Application Matrix: Which applications support which capabilities? Where are gaps? Where is redundancy?

Application Dependency Map: Visual graph of application interconnections. Click on an application to see what it depends on and what depends on it.

Technology Heatmap: Which technologies are where in the landscape? Colour-coded by radar position or support status.

Data Flow Diagram: How does data move through the enterprise? From source to destination through transformations.

Lifecycle View: Applications by lifecycle stage. What's being built, what's active, what's being retired?

Portfolio Health Dashboard: Technical fitness, business value, compliance status across the portfolio.

Roadmap Timeline: Gantt-style view of planned architecture changes over time.

Analysis Views

Impact Analysis: "If we change X, what's affected?" Follow relationships to understand blast radius.

Gap Analysis: Current capability maturity vs target. Where do we need to invest?

Rationalisation Candidates: Applications with low business value and poor technical fitness — candidates for retirement.

Technology Currency: Applications by technology currency — what's on supported versions, what needs updating?

Risk Concentration: Where is risk concentrated? Critical applications on retiring platforms, single points of failure, etc.

Registry Governance

Ownership Model

Data Quality

Registry value depends on data quality:

Completeness: Required fields populated. Key relationships captured.

Accuracy: Data matches reality. Regular validation against actual state.

Currency: Data is up to date. Review cycles enforced. Staleness flagged.

Consistency: Naming conventions followed. Categories used correctly. No duplicates.

Maintenance Triggers

Registry updates should be triggered by events:

Review Cycles

The Governance Core in the Registry

The Architecture Registry isn't just another component of the Governance Core — it's the connective tissue that ties all the other components together. Passports, decision records, technical debt, tiered oversight, guardrails, and risk integration all live in or link through the registry.

Registry role: Summary attributes, relationships, portfolio-level queries Passport role: Full context, detailed documentation, system-level depth

The registry answers "what do we have?" The passport answers "tell me everything about this system."

Decision Records

Decision records are indexed in the registry and linked to affected entities. This creates traceability from decisions to the systems, technologies, and capabilities they affect.

Query examples:

• "What decisions have affected this application?"
• "What applications are affected by this technology decision?"
• "What decisions introduced deviations from security guardrails?"
• "Show me all decisions made in Q3 that introduced technical debt"

The registry provides the index and relationships. The full decision record (with context, options considered, rationale) lives in the linked document or passport.

Technical Debt Register

The registry aggregates technical debt across the portfolio, providing visibility that individual passports can't.

Per-application debt (summary in registry, detail in passport):

Portfolio debt views:

Debt-to-risk linkage:

Every debt item in the registry tracks:

• Risk classification (what risk does this debt represent)
• Risk owner (who's accountable for the risk)
• Acceptance status (tracked, accepted, remediation planned)
• Escalation triggers (when this debt becomes a risk escalation)

This connects the Technical Debt Register to Risk Integration — debt is visible not just as work to be done, but as risk being carried.

Tiered Oversight

Every application in the registry has a tier classification that determines governance intensity:

Tier factor tracking:

Governance implications:

The tier classification drives:

• Review requirements (who must be involved in changes)
• Decision authority (who can approve deviations)
• Documentation depth (how detailed the passport must be)
• Monitoring intensity (how closely it's watched)

Portfolio views show tier distribution — how many Tier 1 vs Tier 2 vs Tier 3 systems, and whether that distribution is changing.

Guardrails

Guardrails live in the registry as first-class entities, with compliance tracked per application.

Guardrail records:

Compliance tracking:

For each application-guardrail combination:

Portfolio compliance views:

• Compliance by guardrail: Which guardrails have the most deviations?
• Compliance by application: Which applications have compliance gaps?
• Compliance by domain: How compliant are we in security vs technology vs data?
• Compliance trend: Are we becoming more or less compliant over time?
• Deviation aging: How long have deviations been outstanding?

Risk Integration

The registry provides the data foundation for architecture-related risk visibility.

Risk surfaces in the registry:

Risk-based views:

Escalation triggers:

The registry can flag when conditions meet escalation criteria:

• Tier 1 application with critical debt item
• Security guardrail deviation older than threshold
• Multiple deviations creating systemic pattern
• Technology approaching end of vendor support
• Debt remediation exceeding budget threshold

These triggers connect architecture governance to enterprise risk management.

How the Components Connect

The registry is the index. It provides portfolio-level visibility, relationships, queries, and aggregation.

Passports are the detail. They provide system-level depth, full context, and operational documentation.

Decision records are the rationale. They explain why things are the way they are.

Debt items are the trade-offs. They track compromises and shortcuts that need attention.

Guardrails are the boundaries. They define what's acceptable and track compliance.

Tiered oversight is the classification. It determines governance intensity.

Risk integration is the lens. It surfaces architectural state as risk exposure.

All of these live in or connect through the registry. That's what makes it the backbone of the Governance Core.

Tool Considerations

When Spreadsheets Work

For small landscapes (under 50 applications), spreadsheets can work:

• Application inventory
• Technology catalogue
• Simple dependency matrix

When You Need Tooling

Invest in proper EA tooling when:

• Application count exceeds ~50
• Dependency analysis becomes critical
• Multiple stakeholders need different views
• Audit/compliance requires formal records
• Roadmap visualisation is needed
• Impact analysis is frequent

Tool Options

Enterprise-grade:

• LeanIX — cloud-native, strong application portfolio management
• Ardoq — flexible metamodel, good visualisation
• Mega HOPEX — comprehensive, heavyweight
• Orbus iServer — Visio integration, strong governance

Mid-market:

• Alfabet — SAP ecosystem integration
• ABACUS — government-focused
• Essential Architecture Manager — open source option

Lightweight:

• Confluence/SharePoint with structure — minimal investment, limited capability
• Custom-built — flexibility, maintenance burden
• Spreadsheets — simplest start, doesn't scale

Selection Criteria

• Metamodel flexibility: Can you model what matters to you?
• Visualisation: Can you see relationships clearly?
• Query/analysis: Can you answer the questions you need to?
• Integration: Does it connect to your other systems?
• Usability: Will people actually use it?
• Cost: Does the value justify the investment?

Common Pitfalls

Modelling everything with equal depth

You don't need the same level of detail for every application. Critical systems need comprehensive records. Peripheral tools need basic registration. Prioritise depth based on criticality and change frequency.

Registry as separate activity

If maintaining the registry is separate from actual architecture work, it won't stay current. Registry updates should be embedded in delivery workflows, project gates, and governance processes.

No relationships, just lists

Lists of applications, lists of technologies, lists of capabilities — without the relationships between them, you have inventories, not architecture. The value is in the connections.

Aspiring to model everything

Don't try to implement the full metamodel on day one. Start with what's most needed (usually application portfolio and dependencies), prove value, then expand.

Tool before practice

Buying an EA tool doesn't create architecture practice. Start with the practice — what do you need to know, how will you maintain it — then select tooling that supports the practice.

Getting Started

Week 1-2: Define scope

• What questions do you need to answer?
• What entities and relationships support those questions?
• What's your minimum viable registry?

Week 3-4: Establish structure

• Define your entity types and key attributes
• Define critical relationships
• Set up your tool (even if just structured spreadsheets)

Month 2: Populate core content

• Application inventory (start with Tier 1)
• Critical integrations
• Technology catalogue with radar positions
• Capability model (at least L1-L2)

Month 3: Add depth

• Expand application coverage
• Add data architecture elements
• Populate reference architectures
• Link to existing documentation (passports, decisions)

Month 4+: Operationalise

• Embed in governance processes
• Establish maintenance triggers
• Build views and reports
• Expand based on demand

The Registry's Role

The Architecture Registry is the structural backbone of Connected Architecture. It provides:

• Visibility: See the landscape — what exists, how it connects, what state it's in.
• Context: Understand why things are the way they are — capabilities, decisions, constraints.
• Analysis: Answer questions — impact analysis, gap analysis, rationalisation, roadmapping.
• Governance: Enable informed decisions — compliance tracking, health monitoring, risk visibility.
• Persistence: Institutional memory — survives team changes, organisational restructures, tool migrations.

Without a registry, architecture is tribal knowledge. With one, it's a managed asset that provides ongoing value.

Model what matters. Maintain what you model. Use what you maintain.

XAF Connected Architecture | Developed by InnovateX Solutions