What is extensibility? A guide to flexible software

That shiny new software package you installed might work perfectly right now, but it’s unlikely to stay that way forever. Over time, components fail, flashy tech starts to feel clunky, and once-innovative features become the norm. 

Instead of overhauling your entire data infrastructure every few years, look into software that prioritizes extensibility. These platforms adapt and grow over time, integrating new functionality without you having to completely rewrite their code.

In this guide, we explore what extensibility is and why it’s such an important part of modern software. 

What is extensibility?

An extensible system is one that’s designed to be adaptable to accommodate future growth. In software, extensibility describes how well a platform embraces new integrations, capabilities, and features over time. 

Some software, such as open-source programs, can be easy to adapt, while other platforms can be more rigid and challenging.

When choosing new systems for your company, here are a few important extensibility characteristics to look out for:

• Extensive documentation: The more information you have about a platform’s code and how it works, the easier it will be to interact with and adapt.
• Backward compatibility: Each new version of the software should iterate on the previous, building on existing architecture so that nothing becomes obsolete.
• Compartmentalized architecture: Apps and programs that break their features down into segments make it much easier to extend, rebuild, or change them to suit your needs.
• Well-defined interfaces: Access to application programming interfaces (APIs) and software development kits (SDKs) allows you to interact with a system without having to change its core code. 

Extensibility vs. flexibility. vs. reusability

While extensibility, flexibility, and reusability are all essential software design principles, they don’t mean the same thing.

Here’s how the three terms differ:

• Extensibility: allows you to add new functionalities, tools, or integrations to software 
• Flexibility: is a focus on versatility, meaning components are designed to work across a range of scenarios 
• Reusability: means developers can reuse existing code or components in other parts of the system, even on entirely different projects 

Why is extensibility important?

Installing entirely new software every few years is inefficient, and rewriting core codebases is timely, expensive, and comes with the risk of jeopardizing your entire system. 

Extensible software can adapt and grow to your requirements and add new features over time, meaning your business won’t “age-out” of a platform or app. You’re able to tweak or update software as and when you need, helping you design the ideal platform for your organization’s specific use cases.

Type of extensibility

Extensibility can take several forms depending on the type of software, your industry, and your company’s specific demands. Some are more hands-on, flexible, and demanding, while others are more stable and consistent.

Here are the main types of software extensibility and when to deploy them.

Internal extensibility

Internal extensibility is the extension of a system’s features by adding your own components. If a platform has unrestricted access, you can freely modify its source code. This level of flexibility does come with risks, as you’ll have to be careful not to introduce errors that might damage the system’s integrity. Internal edits require careful planning, deep knowledge of the code you interact with, and continual maintenance.

External extensibility

When you interact with APIs, plugins, event hooks, or pre-built components, you’re not actually engaging with a product’s core system. External extensibility creates new functions without touching the underlying source code. It’s limited what you can accomplish with external interactions, but this also means that your features are more likely to be stable and scalable.

White box extensibility

White box extensibility is where you have access to a platform or program's source code. This is commonly the case with open-source software. By editing and rewriting parts of the code, you can implement new features and build out different versions to support specific use cases.

Gray box extensibility

In gray box systems, you have partial access to the underlying code, which you can typically access through an API. Features like a content management system (CMS) will allow you to customize and configure the platform without editing its main components.

Black box extensibility

The only edits you can make in a black box system are interactions with external interfaces or pre-built APIs. A partner company could provide you access to a platform without showing you the source code, like when using a third-party SDK for push notifications.

How to choose the right extensible software

While it isn’t usually something software developers advertise, you can gauge the extensibility of a platform by looking at its surrounding environment. 

When working out whether a software option is an adaptable and scalable choice, keep in mind the following:

• Comprehensive documentation: The more documentation you have access to, the easier it will be to understand the full functionality of a piece of software and to edit and add to it.
• Active developer community: Extensible systems often attract thriving online developer communities. This will make it easier for you to find new components that connect to your existing systems.
• Low-code/no-code options: Even non-technical users can build new components and functionalities in low- or no-code environments. These software offerings will help your teams tweak the platform to their needs. 
• Standards compliance: While not necessarily a sign of extensibility, maintaining compliance is a priority for every business, so making sure software accommodates this is extremely important. 

Customize your data pipelines with Fivetran

Your data architecture underpins every single analytics workflow and decision-making process in your organization. Fivetran supports both run-of-the-mill data ingestion services, with over 700 pre-built connectors delivering accurate, timely data, as well as a connector SDK for situations requiring custom connectors, and a REST API for programmatic control. With both standardized, off-the-shelf capabilities and extensibility, you’re able to power your informational systems with the enriched content you need.

Fivetran Extensibility Management helps you extend the capabilities of your data platform even further. In addition to Fivetran’s end-to-end automated pipelines, you’re able to write custom code to fetch data from unsupported sources and trigger external actions.

To see how Fivetran can help you build the ideal data architecture for your business, request a live demo today.

FAQs

What role do APIs and SDKs play in platform extensibility?

APIs and SDKs help developers interact with platforms in a constrained way. They’re well-documented and structured extensibility methods that help you build new features while staying within an expected range of use cases.

What are event handling mechanisms used for in extensible software?

Event handling lets you respond to state changes or respond when specific actions occur in your system. Creating event handling mechanisms means you can let your platform respond in a certain way when each event happens, without needing to hard-code the behavior.

Is open-source software always extensible?

While open-source software does allow you to see the underlying code, that doesn’t mean you can edit it easily without prior knowledge. You could argue that only well-documented code is extensible, as your final product needs to work and scale alongside your system. 

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