Understanding Application Architecture: Concepts, Strategies, and Patterns

In information systems, application architecture is one of 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 deliver.

Application architecture is defined based on business and functional requirements. It involves defining interactions among application packages, databases, and middleware, which helps identify integration issues or gaps in functional coverage and enables migration planning for legacy systems with high technical risk.

The goal is to ensure that the suite of applications used in a composite architecture 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.

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

Strategy

An application architecture strategy ensures that applications and integrations align with the organization’s growth strategy. For example, a manufacturing company expanding through acquisitions needs flexible applications that can incorporate inherited legacy systems and large competitor systems.

Patterns

Key references: Architectural pattern and 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 are placed in a context to solve one or more architectural problems.

Typical industry‑standard application architecture patterns include:

Client‑Server Proxy : Acts as a concentrator for many low‑speed links accessing a server.

Client Support : Supports complex customer interactions across multiple organizations.

Reactor: Separates events from their processing.

Replication Server : Replicates to relieve load on a central server.

Layered Architecture : Decomposes services so most interactions occur between adjacent layers.

Pipe‑and‑Filter : Transforms information through a series of incremental steps or processes.

Subsystem Interface: Manages dependencies among cohesive groups of subsystems.

Self‑Service : Users access transactions on a 24/7 basis.

Collaboration : Users cooperate to share data and information.

Information Aggregation : Aggregates and presents data from multiple sources across multiple channels.

Event‑Centric : Handles data events (originating from devices, applications, users, storage, or clocks) with detection logic that may discard, trigger processes, raise alerts, or update storage.

Business‑Process‑Centric : Manages interactions among multiple internal 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; a rapidly growing organization 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 scenarios, and guiding design decisions.

Competitive Intelligence, Business Modeling, Strategic Analysis

Understands global markets, consumers, industry, competition, and the relationships among business models, strategy, finance, operations, and structure, linking them to organizational vision, culture, value proposition, and strategic requirements.

Technology

Understands IT strategy, development lifecycle, application/infrastructure maintenance, and IT service and support processes to create competitive advantage 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 across several dimensions:

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 full replacement at the end of their technical or functional lifecycle.

Functional Footprint

Understanding the system flow of major business processes, showing a clear map of application footprints across functional diagrams.

Creating Solution Architecture Guidelines

Each organization has a set of core applications that may be deployed as a single instance or multiple departmental instances. A solution‑architecture template for all core applications provides a common starting point for project design and implementation.

Architecture standards are defined in TOGAF, which describes the four EA components (Business, Data, Application, and Technology Architecture). Depending on complexity, other frameworks such as Zachman, Federal Enterprise Architecture (FEA), and Gartner may also be considered.

Other References

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

IEEE 1471 – Architecture description for software‑intensive systems (superseded).

IBM Systems Application Architecture.

Enterprise Architecture Planning.