Key Takeaways
- Base all development on proxying the AEM Core Components. Build custom code only when absolutely necessary.
- Separate presentation (HTL) from business logic (Sling Models) to ensure maximum flexibility and testability.
- Treat component documentation as mandatory API contracts for authors, developers and QA teams.
- Directly connect component governance to faster time-to-market, which ensures a verifiable return on your entire AEM investment.
Most enterprise teams running Adobe Experience Manager (AEM) hit the same wall. Their component library starts clean, then slowly becomes a mess of custom code, duplicated work and unpredictable behavior. This investment, intended to speed things up, has become a stopper.
How?
One team builds a button component for their project. Another team, working on a different site, requires something similar but with slight modifications. So they build their own. Then another team does the same thing. Before long, you’ve got 12 button components, each with its own quirks, its own bugs and its own maintenance burden.
That’s component sprawl. And it kills velocity.
Creating a scalable component library isn’t just a nice-to-have. It’s the foundation for faster releases, lower costs and consistent performance across every business unit. This guide walks through the technical and organizational decisions that turn your component library from a liability into an actual engine for delivery.
Stop the Bleeding: Component Sprawl
Component sprawl happens when teams repeatedly build nearly identical components, each slightly customized for their specific use case. Every bespoke component adds maintenance overhead. It complicates testing and slows down delivery.
A scalable library stops this by making components genuinely reusable. You build once, use everywhere.
Here’s what the difference looks like in practice:
Problematic Library (High Debt)
Teams build components that only work within their specific project site. Business logic, structure and styling are all tangled together. Developers spend time debugging custom, undocumented code. Slow releases become the norm.
Scalable Library (High Velocity)
A single component repository gets used and documented by all teams. Data, logic and view are cleanly separated. New features get assembled using existing, validated components. Releases accelerate.
Learn more: What High-Performing AEM Teams Do Differently
Build on Stability: Core Components First
If you’re building an AEM component library, you must start with the AEM Core Components.
Adobe tests them. Adobe maintains them. Adobe optimizes them. They’re the most stable, performant base you can get. Building from scratch when a Core Component already exists is choosing technical debt unnecessarily.
Start with Proxy, Not Customization
The single most effective move? Proxy the Core Components instead of building similar functionality yourself.
Proxying means creating a new component that inherits all the functionality of an existing Core Component. You only override what you need, like the HTL template or the Sling Model. You never touch the underlying Core code.
Why does this matter? When Adobe updates a Core Component for security or performance, your proxied component automatically gets those benefits. No manual refactoring. No emergency patches. Just stability.
This isn’t a shortcut. It’s the upgrade path that keeps your platform maintainable.
Learn More: How Organizations Improve AEM Efficiency
Enforce Clean Architecture: Separation of Concerns
Scalability requires clean code. That means following the separation of concerns principle, where different parts of your system handle different jobs.
In AEM, this breaks down into two layers:
View Layer (HTL): This only handles presentation and markup. No complex logic. No business rules. No direct data queries. If your HTL template is doing anything beyond displaying variables, it’s doing too much.
Logic Layer (Sling Models): This is your Java class. It fetches content, manipulates data and exposes the necessary variables to the HTL template. All your business logic lives here, isolated and testable.
This separation makes components easy to test, update and understand. When a developer looks at your HTL, they should see structure. When they look at your Sling Model, they should see logic.
Keep them separate. Always.
Govern the System: Centralize and Document
A component library is a shared asset. Its growth needs discipline, centralized governance and strict documentation standards.
Centralize the Repository
Component code must live in a single, well-structured location within your Maven project. Common practice organizes by logical folders:
- core: All Sling Models, backend code and shared utilities.
- ui.apps: All HTL templates, CSS/JS includes and component definitions.
- ui.content: All configuration, policies and sample content.
This structure aligns with the full-stack methodology in AEM as a Cloud Service. It keeps the environment stable and predictable, which is non-negotiable for strengthening AEM operations.
Documentation is Critical
For a component to be truly reusable, everyone needs to know exactly what it does, how to use it and what its limitations are.
Visual Guide: Provide clear, high-fidelity mockups of every component variation. Standard button, primary button, disabled button. Show all states.
Authoring Contract: Document required fields, behavior, policy configurations and accessibility rules for content authors. They need to know what levers they can pull.
API Contract: Developers must document all exposed properties and methods in the Sling Model. This is the internal API. If it’s not documented, it doesn’t exist.
This isn’t busywork. It’s the contract that makes collaboration possible.
Component Excellence Drives Everything
A poorly governed component library guarantees slow delivery and high maintenance costs. We’ve seen teams spend weeks debugging issues that trace back to undocumented, duplicated components.
By contrast, a library built on AEM Core Components, backed by strict separation of concerns and enforced by centralized governance, accelerates your entire digital roadmap. New features get built faster. Bugs get caught earlier. Teams move with confidence instead of caution.
This technical discipline is the single most important factor in securing a platform ready for continuous, enterprise-level delivery.
Ready to redesign your AEM architecture for continuous velocity and stability? NetEffect specializes in setting up the governance frameworks and development standards that transform component chaos into a profitable, scalable digital asset.
Contact NetEffect today to secure your architectural foundation.
Frequently Asked Questions (FAQs)
A proxied component inherits the tested, stable code of an AEM Core Component. You only override what’s necessary, like style or specific behavior. A custom component is built from scratch, meaning you manage all code, security and maintenance yourself. Proxying is the standard for scalability.
Use HTML Template Language (HTL). HTL is security-focused, automatically prevents XSS and enforces the separation of logic from view. It directly supports the scalable component architecture. JSP is legacy. Move on.
A well-architected library with clean Sling Models naturally prepares the platform for headless architecture. The Sling Models can be easily converted to serve content via AEM’s JSON Exporter, making content available to any external framework without requiring redevelopment.
Preventing sprawl requires strict review gates. Developers must justify creating a new component by demonstrating that an existing one cannot fulfill the requirement, even through policy configuration. This organizational rule makes governance effective.
