Source Code Documentation Best Practices

The article was updated on September 06, 2023.

These days, businesses are increasingly reliant on software to drive growth, efficiency, and customer satisfaction. Yet, business owners don’t have to be well-versed in the nuances of software development.

They often rely on third parties to do the technical part for them. The result of such collaboration will greatly impact their abilities to meet business goals. Ensuring that you receive code documentation with the complete project may drastically increase your success chances.

Developers use code documentation to guide the creation and maintenance of software systems, just as designers may use blueprints for their creations. Code documentation involves crucial explanations, insights, and usage instructions embedded into the codebase, making it accessible to both developers and non-developers alike.

Good code documentation ensures the intent, logic, and functions of the code, reducing the risk of misinterpretation and costly errors. It is also essential for productive and efficient collaboration between developers, helping with bug fixing, code reviews, and other maintenance processes.

Overall, by following documenting code best practices, businesses can ensure the success of their software development process.

In this article, we’ll explore how code documentation can contribute to the success, efficiency, and easy maintenance of your software projects. Here is what you need to know.

What is code documentation?

Code documentation is the practice of adding explanatory messages to software’s source code. Such a practice serves as guidance to all the developers who work on a project at the moment or who will be in the future. Such documentation includes comments, explanations, and instructions.

By documenting code, developers explain how the code works, what its purpose is, and how to use it effectively. It also brings order and reduces any chances of confusion or misunderstanding during maintenance and when the code is updated in the future.

Well-documented code also facilitates the onboarding of new team members and aids in troubleshooting issues. Moreover, writing code documentation also contributes to the longevity of a project, enabling future developers to comprehend and build upon existing code, even as technology evolves.

In essence, code documentation is a vital tool for efficient, clear, and sustainable software development.

Why do you need code documentation?

Despite a common misbelief, code documentation is used to describe not “WHAT the code does?”, but “HOW it does it?” Its main purpose is to increase the product’s maintainability, regardless of who might be working with the code.


There are several reasons why code documentation is crucial for any project:

  • Knowledge transfer. Code documentation helps preserve the knowledge and expertise of developers, ensuring that code is readable by any expert outside the developing party. It allows external developers to understand the codebase and make necessary changes without requiring additional assistance. Thus, it facilitates the smooth transfer of knowledge to the customer or new team members, reducing onboarding time and maintaining productivity.
  • Maintenance and troubleshooting. Software projects require ongoing maintenance and updates. Well-documented code makes it easier to identify and fix bugs, address issues, and make enhancements. Documentation helps developers quickly grasp the code’s intent, answering the ‘HOW’ question, and making the maintenance process more efficient.
  • Integrations and product add-ons. Clear documentation ensures smooth integration of the developed software with existing systems, reducing implementation time and costs. It facilitates the seamless addition of product add-ons or extensions, enabling easy customization that meets specific needs without embarking on new development cycles.
  • Scalability and growth. As businesses grow, their software systems often become more complex. Code documentation ensures that as the codebase expands, developers can still understand and work with the code effectively. It helps maintain consistency in coding standards.
  • Collaboration. Comprehensive code documentation provides up-to-date insights on the ongoing work, ensuring easy collaboration among team members. It is written during the work processes, serving as a common reference point to explain everyone’s contributions and intentions, enabling easy collaboration.
  • Long-term sustainability. Code documentation ensures the long-term sustainability and longevity of the project. Over time, as technologies evolve and original developers move on, having well-documented code ensures that the project can continue to adapt and thrive, reducing the risk of becoming obsolete.

All in all, having your application properly documented will make the development and maintenance efforts more efficient and will save you time and money in the long run.

Read also: How To Reduce App Development Cost


At Eastern Peak we always pay special attention to source code documentation. If it is done properly and it is understandable, your in-house developers, as well as other teams you decide to hire won’t have any problems working with it.

Remember, that poor code documentation or its complete lack thereof, is one of the signs that your vendor might be dishonest. They might use this down the road to leverage their position over you and prevent you from switching providers. If the code is properly documented, your current development team can be easily replaced. If it is not, you are trapped.

Here is an example of a properly documented API that we have created for one of our clients, Cloudify.


Types of code documentation

Effective communication between developers, stakeholders, and users is everything. This is where the different types of code documentation come into play, serving as the connective tissue that ensures clarity, collaboration, and successful project outcomes.

For business owners navigating the tech landscape, understanding these various types of documentation can be a strategic advantage. So here is how to create documentation for code based on your desired outcomes.


Internal code documentation

Internal code documentation provides insights and context for developers working directly on the codebase. It provides guidance, offering explanations of complex algorithms, decision-making processes, and specific technical nuances. This type of documentation fosters consistency and empowers developers to make informed choices.

External code documentation

Just as a well-structured business proposal appeals to potential investors, an external code document showcases the value of your software to users, clients, or other developers.

This type of documentation takes the form of API references, user guides, and tutorials. It highlights how to interact with your software, simplifying its adoption and use.

Low-level or inline documentation

Low-level or inline documentation provides highly detailed explanations directly within the code. These comments clarify the purpose of individual functions, classes, or lines of code, making it easier for developers to decipher the nitty-gritty details.

High-level documentation

High-level documentation of code outlines strategic goals and provides an overview of your software’s architecture, design principles, and major components. It’s the roadmap that guides developers in understanding the broader picture while navigating complex technical issues.

Walkthrough documentation

Like a step-by-step guide through a complex business process, walkthrough documentation offers tutorials and examples that lead developers through specific tasks or scenarios.

It helps developers gain practical insights into the usage and functionality of the code.

Source code documentation best practices

Effective source code documentation is crucial for software projects. However, the keyword here is effective. Knowing how to write source code in project documentation is a skill to master.

These best practices show how to write a documented code that is clear, valuable, and effective. 

1. Write clear comments

Comments act as annotations in your code, explaining its nuances and reasoning. When faced with complex logic or deviated algorithms, clear comments can make a world of difference in comprehension.

Use them to clarify intentions, potential errors, and decision-making. Yet aim for a balance. Avoid over-commenting. Keep it simple, concise, and clear to reduce confusion.

2. Tailor your documentation

Adjusting documentation to different user groups based on expertise levels helps keep it accessible and easy to read for everyone involved. It allows users to explore details gradually as they advance, ensuring engagement for diverse audiences.

Using specific structure types in documentation, such as breaking down information based on information types, can also help effective documentation navigation and readability.

3. Update continuously

Synchronization between code and documentation is essential. Outdated documentation is just as bad as no code documentation at all. It only leads to confusion as developers rely on inaccurate information. Regular updates of the documentation should reflect any modifications made to the codebase, keeping everyone involved informed.

4. Use Documentation as Code (DaC)

DaC is a modern practice that treats documentation in a manner similar to how code is treated. Hence, this technique teaches developers how to write code documentation just as they do with the code itself.

Hence, they apply the same tools, store it in the same version control system, and apply the same practices as during coding. This practice makes documentation an integral part of development, enhancing accuracy, and reducing discrepancies.

5. Be concise

Consistency in documentation structure and style is essential for creating a cohesive and understandable codebase. Consistent naming conventions, and a uniform formatting style for comments, docstrings, and other documentation elements is the key to helpful insights and productive cooperation.

Lastly, follow the DRY (don’t repeat yourself) method when documenting to keep it simple and short. Such consistency makes it easier for developers to quickly locate information, understand the documentation’s layout, and navigate through the codebase effortlessly.

6. Provide prerequisite information

Ensure that any new users have the necessary knowledge and tools to effectively use your code. Provide a list of libraries, programming languages, necessary tools, compatibility details, system requirements, troubleshooting guidance, and more.

Keep this information up to date to ensure users can easily set up the required environment and use your code effectively.

7. Use docstrings

Docstrings are a developer’s equivalent of a user manual. They provide detailed explanations of their purpose, inputs, usage, etc. Code documentation standards include docstrings to help other developers understand how to interact with the code.

8. Utilize automated documentation tools

Utilizing automated tools for code documentation like Doxygen, Javadoc, or GhostDoc can speed up the documentation process enhancing their effectiveness and comprehensiveness.

Slate and Swagger are among the most popular tools for API documentation.

However, it’s essential to combine automated generation with human input, to provide more personal and nuanced insights. The blend of human touch and automation creates technically accurate and user-friendly documentation, encouraging effortless knowledge transfer among all parties.



Some teams may prefer to skip code documentation in order to save time, money and effort. Keep in mind though that this might result in even more significant expenses once the product is transferred to another team or when updates are required down the line.

We at Eastern Peak always document the source code we create for our clients, following the best practices described above. Using the dedicated team approach, we can efficiently and effectively cooperate with your in-house team or transfer the deliverables as soon as development is completed.

Book a consultation with our project manager to find out how our team can help you build better software. We will be happy to provide references and examples of our work on request.

Frequently Asked Questions

Should code have documentation?

Yes, code should have documentation. Documentation enhances code comprehension, collaboration, and maintenance by providing insights into its purpose, behavior, and usage.

How do you write software code documentation?

To write effective software code documentation, use meaningful names for elements, add clear comments to explain logic, employ docstrings for functions and classes, and focus on explaining the intent behind design choices rather than just implementation details.

What are the tools for code documentation?

Tools like Doxygen, Javadoc, Sphinx, and various integrated development environments (IDEs) offer features to generate and manage code documentation. These code documentation tools help automate the documentation process and ensure consistency.

What is an example of code documentation?

The code documentation examples include internal, external, and walkthrough code documentation. They follow different goals, such as giving additional instructions or warnings, explaining the intent, or elaborating on the code’s purpose.

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