Application Architecture: Concepts, Strategies, Patterns, and the Role of Application Architects

In information systems, application architecture is one of the domains that constitute the pillars of enterprise architecture (EA).

Application architecture describes the behavior of the applications used in a business, emphasizing how they interact with each other and with users, and focusing on the data they consume and generate rather than their internal structure. In application composition management, applications are mapped to business functions, processes, cost, functional quality, and technical quality to assess the value they provide.

Application architecture is defined according to business and functional requirements. This involves defining interactions between application suites, databases, and middleware based on functional coverage, helping to identify integration issues or gaps, and creating migration plans for legacy systems that are at the end of their software lifecycle or carry inherent technical risk.

The goal is to ensure that the composite architecture of the application suite is scalable, reliable, available, and manageable.

Application architecture defines how multiple applications work together, which differs from software architecture that deals with the technical design of how a system is built.

Practitioners must understand and manage the dynamics of the composite architecture’s functionality, help devise deployment strategies, and monitor technical risks that could threaten organizational growth or operations.

Strategy

Application architecture strategy includes ensuring that applications and integrations align with the organization’s growth strategy; for example, a manufacturing firm expanding through acquisitions needs flexible applications that can incorporate inherited legacy systems and competing large‑scale solutions.

Patterns

Main article: Architectural pattern (https://en.wikipedia.org/wiki/Architectural_pattern)

Further information: Software design patterns (https://en.wikipedia.org/wiki/Software_design_patterns)

Based on the architectural pattern an application follows, it can be classified into various types. A “pattern” is defined as an idea useful in a real environment and potentially useful in other environments.

Creating a pattern requires building blocks—reusable software components that can be assembled to provide certain functionality. A pattern describes how to place these building blocks in context to solve one or more architectural problems.

Applications typically follow industry‑standard application architecture patterns, such as:

Client‑proxy server: a hub for many low‑speed links accessing a server.

Client support: supports complex customer interactions across multiple organizations.

Reactor: separates events from their handling.

Replication server: offloads the central server.

Layered architecture: decomposes services so most interactions occur between adjacent layers.

Pipe‑and‑filter: transforms information through a series of incremental steps.

Subsystem interface: manages dependencies between cohesive groups of subsystems.

Self‑service: users access transactions 24/7.

Collaboration: users cooperate to share data and information.

Information aggregation: aggregates data from multiple sources across channels.

Event‑centric: handles data events, detects conditions, triggers processes, alerts users or devices, and updates stores.

Business‑process‑centric: manages interactions among enterprise applications, services, sub‑processes, and users.

Batch processing: manages interactions between one or more batch data sources and targets.

Extended enterprise: manages interactions among applications, services, sub‑processes, and users across multiple enterprises.

Strangler pattern: incrementally replaces legacy functionality with new applications and services, eventually retiring the old system.

The appropriate pattern depends on the organization’s industry and how its component applications are used; an organization that grows organically and through acquisitions may employ multiple patterns.

Application Architect

An application architect is a leader or technical manager in a software development team responsible for building applications and the technologies they use.

Knowledge Areas

Application Modeling

Uses modeling as a framework for developing new or enhanced applications, discovering problems, reducing risk, improving predictability, lowering cost and time‑to‑market, testing product scenarios, incorporating customer requirements, adding test‑design decisions, and evaluating product design issues.

Competitive Intelligence, Business Modeling, Strategic Analysis

Understands global markets, consumers, industries, competition, and the relationships among business models, strategy, finance, operations, and structure; assesses strengths, weaknesses, opportunities, and risks in the competitive environment.

Technology

Understands IT strategy, development lifecycle, application/infrastructure maintenance, and IT service and support processes to enhance competitive advantage, efficiency, and business value.

Technical Standards

Knows the key technologies required to support current and future business needs, ensures hardware and software meet baseline requirements before integration, and can define standards and guidelines for adopting new technologies.

Tasks

The application architect provides strategic guidance for all aspects of applications, focusing on:

Interoperability

Performance and scalability

Reliability and availability

Application lifecycle stage

Technical risk

Instance count

This analysis identifies applications that need changes—from deployment‑strategy adjustments to complete replacement at the end of their functional or technical lifecycle.

Functional Footprint

Understanding the system flows of major business processes shows a clear map of each application’s functional footprint.

Many organizations lack documented procedures, resulting in missing detailed business‑process and system‑flow diagrams, which may require initiating an effort to create them.

Creating Solution Architecture Guidelines

Each organization has a set of core applications that may be used as a single instance or multiple instances across departments. A solution‑architecture template for all core applications provides a common starting point for design implementation across projects.

Architectural standards are defined in TOGAF, which describes the four EA components (business, data, application, and technology architecture). Depending on organizational complexity, other standards such as the Zachman framework, Federal Enterprise Architecture (FEA), and Gartner may also be considered.

Other Aspects

ISO/IEC 42010 – Systems and software engineering – Architecture description.

IEEE 1471 – Standard for describing the architecture of a software‑intensive system.

IBM Systems Application Architecture.

Enterprise architecture planning.