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Dependency mapping: A beginner's guide

Organizations everywhere use open source to expedite development, lower costs, and improve performance. Our annual State of the Software Supply Chain reports consistently reaffirm that open source comprises up to 90% of modern software solutions.

However, enterprises also take on more open source risk as they lean more on open source software. Security concerns abound with leveraging open source components in software supply chains.

Ironically, perception remains disconnected from reality as data reveals a significant gap often exists between perceived and actual software supply chain maturity within organizations. Many organizations tend to overestimate their readiness for handling open source dependencies, fostering an illusory sense of security in their practices.

To emphasize this point, observe that the highly regulated finance industry has formed an Open Source Readiness special interest group specifically to address the risks and hurdles associated with the adoption of open source software.

In this context, development teams must thoroughly map software dependencies — the open source libraries and packages your code depends on — to effectively track their software's different relationships and connections. Dependency mapping is critical for preventing security vulnerabilities like Log4j as well as predicting how licenses and updates impact performance.

If you want to learn more about dependency mapping, check out the fundamentals below. This blog post explores what dependency mapping is, the benefits of mapping dependencies, and some tools that make the process easy.

Understanding dependency mapping

Dependency mapping is the process of identifying and visualizing all software dependencies within an application.

Similar to a software bill of materials (SBOM), dependency mapping creates a comprehensive inventory of all external dependencies used in a software project. But mapping intends to provide a clearer picture of which components rely on others and how changes or updates in one component can affect the overall system.

Dependencies can include open source external libraries, modules, or code components incorporated into a software project to extend its functionality, improve efficiency, or achieve specific tasks.

Types of dependencies

In the context of mapping, there are two types of software dependencies to consider:

  • Direct dependencies: Software dependencies explicitly defined and utilized by a software component.
  • Transitive dependencies: Libraries or modules that indirectly contribute to a software component’s functionality.

Transitive dependencies typically pose a more significant challenge for developers. Detecting them can be an arduous task, especially in the absence of specialized tooling. With this in mind, it is critical to try to reduce complexity and dive deeper into the software supply chain to uncover possibly hidden dependencies.

Think of ignoring a transitive dependency as securing the front door of an office while unknowingly leaving a window open at the back. To safeguard your applications from potential threats, it is essential to address vulnerabilities comprehensively, not just the obvious ones.

By mapping dependencies at the code level, organizations can gain greater clarity into the different underlying parts and services that make up their applications — including component origination, individual authors, and version updates (or lack thereof).

What are the benefits of dependency mapping?

In the context of open source software, dependency mapping helps developers and organizations better understand the ecosystem of open source components they use. This insight enables proactive issue resolution, ensures compliance with licensing requirements, and upholds a high standard of software quality and reliability.

As we recently reaffirmed in our 9th annual State of the Software Supply Chain, a staggering 96% of all known-vulnerable open source software downloads were entirely avoidable. In the case of Java components in Maven Central, developers consume 2.1 billion avoidable vulnerable dependencies every month.

At the same time, threat actors rapidly advance their ability to discover and exploit vulnerabilities. Looking ahead, most security executives predict a rise in cyberattacks from ransomware and social engineering tactics. These attacks target misconfigurations, lapses in maintenance, human error, and unknown assets.

While it may be challenging to thwart every incoming cyber threat, the power to seal the gaps in your software's defenses begins with dependency mapping. By doing so, you give yourself the best chance to prevent threat actors from exploiting these openings and gaining unauthorized access to sensitive data.

Besides enhancing security, we cover four additional benefits to dependency mapping below.

Reduce downtime caused by software changes

Removing or altering software components can inadvertently lead to application downtime, which not only disrupts operations but also has cost implications and negatively impacts the user experience. Dependency mapping equips developers with insights to make changes without causing disruptions, scheduling maintenance during periods of minimal user activity.

Deploy dependencies without fear of dependency hell

Dependency mapping doesn't aim to eliminate dependencies, as they often serve to streamline development and reduce costs. Instead, it empowers developers to prune unnecessary dependencies and ensure that the ones they retain are both secure and efficient. This in turn bestows developers with the confidence to deploy dependencies without apprehension.

Reduce testing complexities of software supply chains

Rigorous software testing is imperative to identify security and performance issues. However, testing can become a complex ordeal when dealing with intricate software supply chains. Dependency mapping simplifies the process by providing a comprehensive view of dependencies. This facilitates the selection of appropriate test cases and enhances the understanding of how code adjustments reverberate throughout the system.

Minimize the risk of vulnerabilities 

Dependency mapping isn't merely about the present. It also holds the key to a more secure future. By meticulously scrutinizing code dependencies, development teams may unearth latent vulnerabilities within popular libraries or packages. This proactive approach empowers teams to make informed choices, circumventing rework and averting potential security pitfalls in future applications.

What are common challenges in dependency mapping?

Deciding to map dependencies can lead to transformative results for development teams. However, many teams struggle to optimize the mapping process.

Let's delve into some of the common challenges that companies frequently encounter when undertaking dependency mapping.

Maintaining dependency maps

Ongoing maintenance and updates of dependency maps can be a cumbersome endeavor when executed manually. It not only consumes valuable time but also introduces the risk of costly errors. To overcome this, many teams turn to purpose-built tracking tools, which automate the process, expediting dependency mapping while enhancing precision.

Managing technical debt

Dependency mapping has a knack for shedding light on underlying code issues, often necessitating refactoring. While this is a constructive step toward software improvement, it can accrue technical debt. Technical debt, if left unchecked, hampers productivity and prevents developers from venturing into new projects. To mitigate this, it's crucial to remain vigilant with dependency mapping and promptly address changes to prevent the accumulation of substantial backlogs, which can culminate in bottlenecks.

Visualizing code changes

The intricacies of software development are such that even minor code adjustments can have far-reaching implications within an application. Developers, particularly in the context of complex applications, often grapple with discerning the potential impact of these changes during the iterative process. To counter this challenge, employing specialized software to gain a comprehensive understanding of how adjustments affect performance before moving them into production becomes an essential practice.

Tools for dependency mapping

There are a range of tools available to streamline dependency mapping, enhance the process, and drive better results. Consider the following open source options when assessing dependency mapping services.


Graph for Understanding Artifact Composition (GUAC), a project from Kusari and Google, stands as a robust solution that collects software security metadata, such as SBOMs and SLSA attestations, and provides a high-fidelity graph representation. This tool empowers developers with comprehensive insights and visualizations to better secure their software supply chains.

By facilitating a deeper understanding of dependencies, GUAC equips development teams to proactively manage and secure their software components, fortifying their defenses against potential vulnerabilities. To further explore the capabilities and benefits of GUAC, visit their website or GitHub repository.

Open Source Insights (

Open Source Insights, popularly known as, serves as a valuable tool that maps the dependencies of millions of open source software libraries and flags any unpatched vulnerabilities. Also backed by Google, this tool provides a comprehensive view of open source dependencies in your software projects. aids developers in assessing and visualizing dependencies, enabling better decision-making for enhanced software security and performance. To learn more about this project, explore its website and its documentation.

Sonatype: Streamlining the software supply chain

When forming a dependency mapping strategy, gaining as much visibility into the software supply chain as possible is necessary.

You can leverage a scanning methodology and employ best practices of dependency management. But the right tool can make all the difference.

Sonatype Lifecycle enables you to automatically know the exact location of any software dependency and remediate open source vulnerabilities throughout the software development life cycle (SDLC). This precise intelligence accompanies an evolving vulnerability database to help your team discover threats and take preventative action before attacks take place.

While allowing you to control open source risk throughout your SDLC, Sonatype Lifecycle integrates with various popular development and pipeline tools, making it easy and convenient to use within any development stack.

Additionally, Sonatype Nexus Repository can further enhance your software supply chain. Nexus Repository provides the capability to inspect component dependencies with precision, adding an extra layer of confidence to your development processes.

For more information on how Sonatype can transform your software supply chain, book a demo today.

Picture of Aaron Linskens

Written by Aaron Linskens

Aaron is a technical writer on Sonatype's Marketing team. He works at a crossroads of technical writing, developer advocacy, software development, and open source. He aims to get developers and non-technical collaborators to work well together via experimentation, feedback, and iteration so they can build the right software.