Why Writing Your Own Tools is More Important Than You Think

Published at Sep 10, 2024
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In today’s fast-paced development world, the allure of third-party libraries and tools can be hard to resist. Why spend time writing your own code when you can quickly drop in a well-documented, pre-built solution? For developers under tight deadlines, these external libraries seem like the perfect answer. However, there are hidden risks to relying on third-party tools that can undermine the longevity, security, and flexibility of your project.

In this post, we’ll explore why it can be more beneficial to write your own tools, the dangers of over-relying on third-party libraries, and how to strike a balance between efficiency and long-term code quality.

Control Over Code and Functionality

When you write your own tools, you have complete control over the functionality and how it integrates with your system. Third-party libraries are often a black box: you may understand the high-level API, but what happens under the hood? By writing your own tools, you can ensure that every function, method, and class behaves exactly how you expect it to. No unexpected behaviors, no side effects, and no mysterious bugs caused by dependencies.

Customization and Flexibility
Your project is unique. Pre-built solutions can work well for generic cases, but there’s often a point where you need something more tailored to your needs. Custom-written tools can be built to serve your specific use case without the added complexity and overhead that often comes with bloated third-party libraries.

Security Risks

When using third-party tools, you inherit their security vulnerabilities. Open-source libraries, while transparent, can contain security flaws that go unnoticed until they are exploited. Even well-maintained libraries can have vulnerabilities that bad actors can use to breach your systems.

For example, a popular NPM package, event-stream, was hijacked to introduce malicious code targeting Bitcoin wallets. Developers using this library unknowingly distributed compromised software, showing how easily a dependency can become a threat vector. Writing your own code minimizes the risk of introducing a supply chain attack into your project.

Dependency Hell

Relying on too many third-party libraries can lead to “dependency hell.” This term refers to the situation where your project has conflicting dependencies, or a third-party library is no longer maintained, leaving you stuck with outdated code. Over time, your project becomes harder to maintain and upgrade, as each dependency might break compatibility with others during version updates.

Example: The Left-Pad Incident
One of the most infamous cases of dependency hell was the removal of the left-pad package from NPM. This small utility was used by thousands of projects, including major ones like Babel and React. When the package was unpublished, it caused widespread outages across the ecosystem. Projects that had baked left-pad into their stack were left scrambling to fix their builds.

This shows how something as simple as a 10-line utility can disrupt the entire development community when it’s treated as an external dependency.

Technical Debt

Third-party libraries often come with more features than you need, which can lead to increased complexity in your codebase. Relying heavily on external tools can also contribute to technical debt, as these tools may evolve or become obsolete, forcing you to constantly refactor your code to maintain compatibility. When you write your own tools, you can keep your codebase lean and avoid unnecessary complexity.

Maintainability
Over time, third-party libraries may stop being maintained, leaving your project with no easy path forward for updates or bug fixes. By owning your tools, you guarantee long-term maintainability, as you can adjust and improve your code based on your project’s needs without waiting for external contributors to fix bugs or roll out updates.

When to Use Third-Party Libraries

While writing your own tools offers significant advantages, it’s not always practical or efficient. Certain well-established libraries save time, reduce boilerplate code, and provide battle-tested solutions to common problems. The key is knowing when to use them and when to roll your own.

1. Avoid Reinventing the Wheel
When working on non-critical features, such as logging, authentication, or data parsing, using third-party libraries can speed up development without introducing significant risks. For example, using a library like bcrypt for password hashing is preferable to rolling your own, as security-focused libraries benefit from expert review and continuous updates.

2. Check the Community and Maintenance
If you do decide to use a third-party tool, make sure it’s actively maintained with a strong community around it. Look for libraries with frequent updates, high GitHub stars, and a responsive issue tracker. This ensures that bugs will be addressed promptly and that you won’t get stuck using an outdated tool.

3. Choose Libraries with Fewer Dependencies
Favor libraries that have minimal dependencies. The fewer external dependencies a tool brings into your project, the less risk you have of entering dependency hell. Smaller libraries that focus on one specific task tend to be easier to integrate and manage in the long run.

Finding the Balance: Safety vs. Speed

In the end, development is all about balance. While writing your own tools is an investment in the future stability and security of your project, it’s not always the best choice for everything. Knowing when to leverage third-party libraries for non-core functionality and when to write custom code for critical components is a key skill for any developer.

Key Questions to Ask:

• Is this feature critical to my application’s core functionality?
• How complex would it be to implement in-house?
• How active and well-maintained is the third-party library I’m considering?
• Can I audit the library’s code to ensure security and reliability?
• How many dependencies will this library bring into my project?

By answering these questions, you can strike the right balance between speed and safety, ensuring that your project remains secure, maintainable, and scalable in the long term.

Conclusion
Writing your own tools gives you control, flexibility, and peace of mind, especially for critical components of your project. However, not every problem warrants building a solution from scratch. Use third-party libraries judiciously—stick to well-maintained, minimal-dependency libraries for non-core functionality and write your own tools for everything else. By finding this balance, you can create robust, secure software that stands the test of time.

Happy coding!