Internal documentation in software engineering: 3 tips for success

What is internal documentation?

On the surface, internal documentation is non-public information and knowledge written for internal teams. Beneath the surface, however, internal documentation is the source of truth that keeps people, products, and processes in alignment.

Successful companies—and especially their software development teams—live and die by internal documentation. Though “internal documentation” usually refers to technical documentation, it may also be created, maintained, and consumed by a variety of teams across an organization. This can include human resources, finance and accounting, and even building security.

The article is part of a series of articles about code documentation.

Why is internal documentation in software engineering important?

Internal documentation is important for software engineering teams because it is where they can find and reference key details about their work. This may include:

  • Technical specifications
  • Design documents
  • Sequence diagrams
  • Code commentary and best practices
  • CI/CD pipeline details and instructions

Software engineers rely on internal docs for several reasons. First, and perhaps most importantly, it ensures that everyone understands how software projects are designed, built, maintained, and operated. Like any other project, there are goals, requirements, and non-technical details, all of which need to be kept somewhere accessible to teams and stakeholders. Engineers need quick and reliable access to all this information as they navigate and divide work across complex projects.

Second, engineers need a record of decisions and design choices made during the development process. This is valuable when team members need to understand why features were built and delivered in certain ways. When code needs to be updated months later, a developer can review the internal documentation before asking, “Why again did we do it this way?”

Third, internal docs improve software quality. When teams can access and compare design and implementation details, they can identify inconsistencies, identify opportunities, and ensure that the software aligns with project expectations and user needs. Proactive development relies on documentation and ultimately results in higher quality software.

Fourth, internal docs allow for teams to easily and clearly share an interface, where each team can use the other’s services without relying on their availability for questions.

Tips for internal documentation in software engineering

The three most significant tips for internal documentation in software engineering are:

  1. Ensure the docs are comprehensive, accurate, and up to date
  2. Consistent formatting, language, and presentation
  3. Written for consumers of the documentation

Comprehensive, accurate, and up-to-date documentation

Developers need reliable information that they can trust. It provides the foundation for accurate and complete software development. Unfortunately, most documentation is outdated quickly after it’s written because code is usually copied and pasted, or not referenced explicitly at all. Unless the docs are synchronized with the actual code, pasted code is outdated as soon as the next commit is made to the repo. If no explicit references to the code are made, the docs are liable to be outdated as a result of the implications of the changed code.

If documentation isn’t easy to maintain and update, it doesn’t get maintained or updated. Docs should be kept in a central location where it can be easily accessed and updated. It may also be helpful to establish clear processes for updating the documentation, to ensure that it remains accurate and up to date as the project progresses.

Consistent formatting, language, and presentation in documentation

Good docs should be written in clear, easy-to-understand language. Every document should be organized to make it easy to find when someone is searching or navigating a file structure. It should be accessible to the people who need it. And it should be readable and easily understood by the person who needs it.

Thorough documentation includes graphics, diagrams, code samples (preferably with syntax highlighting), and other visual aids that make information easier to understand and digest. It may also include integrations with other tools and software packages that aid in the production of the product.

Furthermore, it’s important that docs are consistently formatted using Vale, for example, so the reader knows what to expect and where to find what they need without going on a wild goose chase.

Docs should be written for the intended reader

Different readers have different needs and expectations. For example:

  • a software developer might need to know how functions are named and which objects are used for what purposes.
  • a project manager might need to know which functionality has been completed and what remains to be done.

These are two entirely different readers with entirely different needs. Even when the reader is an engineer, there is a substantial difference between an engineer who needs to use the code in question, and an engineer that needs to contribute to it. Good documentation is written to be relevant for all members of a team.

Keeping documentation up to date and easily accessible with Swimm

Here’s what we know: the bigger the company, the greater the need for comprehensive, accurate, up-to-date, consumable, accessible documentation. There’s just no other way to go about it; large software projects are too complex.

Swimm is the world’s first code-coupled Continuous Documentation platform. It’s intelligent to know when code changes affect documentation and vice versa. There’s no more powerful tool for building fantastic internal docs. We have built a sophisticated ecosystem that integrates documentation with popular IDEs, code repositories, and the live code itself.

Swimm docs live in the same repository as the code, offering developers total control and flexibility over structure, presentation, and peer review via pull request. With Swimm, documentation becomes a first-class citizen living side-by-side with the code. Always updated, always consistent, always human readable.

Want to get started with the world’s first Continuous Documentation platform? Sign up for a free account today.