application-architect

# Skill: Application Architect The Application Architect owns the **application domain** of the enterprise architecture (TOGAF ADM Phase C, Application Architecture): the portfolio of applications, their structure, standards and lifecycle — distinct from the infrastructure beneath them and from the structure of one software system. --- ## 1. When This Skill Applies - Owning the application portfolio map and lifecycle (invest, maintain, retire). - Defining application standards, patterns and reference architectures. - Guiding application modernization and rationalization. - Ensuring application-to-application integration coherence. - Assessing build-versus-buy and SaaS fit. - Aligning applications with business capabilities. Does NOT apply to: the internal structure of one system (use [software-architect](../../../roles/software-architect/SKILL.md)), or the integration style between systems (use [integration-architect](../integration-architect/SKILL.md)). --- ## 2. Portfolio Thinking - **Map**: every application, its capabilities served, its criticality and its technical health. - **Lifecycle**: time-based invest/maintain/retire decisions tied to business value and risk. - **Rationalization**: eliminate overlap and duplication before adding systems. - **Build vs. buy vs. SaaS**: decide by fit, differentiation and total cost of ownership, not by preference. --- ## 3. Method (TOGAF ADM Phase C, Application Architecture) 1. **Baseline** the application portfolio and its interfaces. 2. **Target** the portfolio aligned to the business capabilities and the enterprise target state. 3. **Gap analysis** with a rationalization and modernization plan. 4. **Govern** application standards and reusable reference architectures. 5. **Feed** the portfolio decisions to the enterprise architect for the investment plan. --- ## 4. Orchestration and Handoffs | Concern | Owning skill | |---|---| | Enterprise frame and portfolio investment | [enterprise-architect](../../enterprise/enterprise-architect/SKILL.md) | | Internal structure of one system | [software-architect](../../../roles/software-architect/SKILL.md) | | Cross-system integration and messaging | [integration-architect](../integration-architect/SKILL.md) | | API standards and lifecycle | [api-architect](../api-architect/SKILL.md) | | Data model of the portfolio | [data-architect](../data-architect/SKILL.md) | | Domain boundaries and bounded contexts | [architecture-ddd](../../../engineering/practices/architecture-ddd/SKILL.md) | | Enterprise application patterns | [dp-* patterns](../../../engineering/patterns/dp-structural-patterns/SKILL.md) | --- ## 5. Reference Frameworks - **TOGAF** — ADM Phase C, Application Architecture. - **ArchiMate** — Application layer (application component, interface, service). - **C4 model** — for describing a solution's containers and components. - **Enterprise application patterns** — the classic application-pattern catalogue (resolve the edition; see `version-freshness`). See [ea-frameworks](../../enterprise/enterprise-architect/references/ea-frameworks.md). --- ## 6. Common Mistakes | Mistake | Correction | |---|---| | Adding an application before rationalizing | Rationalize overlap first | | Treating the portfolio as an inventory only | It carries lifecycle and value decisions | | Choosing build/buy by preference | Decide by fit, differentiation and TCO | | Confusing application with solution | A solution may span several applications | | No interface governance | Interfaces are governed by the integration architect |