What is API Documentation?

An Application Programming Interface (API) is a set of protocols and tools that software developers use to establish connections between different applications. Upon leveraging an API, developers can facilitate communication and data exchange in a standardized and efficient manner. APIs can simplify the app development process by providing pre-established functionality for developers to integrate into new apps. Additionally, APIs help organizations overcome technical barriers that may impede collaboration and innovation. Through a common set of definitions and protocols, APIs enable businesses to connect various applications used in day-to-day operations, saving employees time and resources.
API Documentation Diagram
API Diagram adapted from Eising, 2017

However, it is important to note that this convenience doesn’t come for free: simply understanding how to use an API can be challenging. Correspondingly, API documentation emerged to provide instructions on how to use and interact with an API, including functionalities, inputs, output formats, and error handling.

The documentation’s importance lies in its capacity to help developers navigate the features and functionalities of APIs effectively. Ideally, well-written and comprehensive documentation can also reduce development time, minimize errors, and improve the overall quality of the software that uses the API.

Good API Documentation Provides Several Benefits for Both Developers and Organizations

  1. Improved Developer Experience
    Ensures a smooth developer experience by providing comprehensive and accurate information about the API’s functionality, behavior, and usage.
  2. Increased Productivity
    Developers can quickly understand and use the API, reducing the time and effort required for development.
  3. Better Collaboration
    Facilitates better collaboration between developers, enabling them to work together effectively and share knowledge about the API.
  4. Lower Support Costs
    Significantly reduce the support costs associated with an API, as developers can quickly find answers to their questions and resolve issues on their own.
  5. Increased Adoption
    Help increase the adoption of an API by making it easier for developers to use and integrate into their projects.
  6. Improved Security
    Help improve the overall security of an organization’s software ecosystem.

Where Did API documentation Come From?

Back in the early days of software development, developers would typically write their own documentation for their APIs. They often used simple text files or basic HTML pages to describe the API’s functionalities and usage.

In the 1980s and 1990s, as software development became came into maturity, documentation started to become increasingly crucial. This was partly due to the rise of object-oriented programming. It increased the requirement for more detailed documentation to describe the interactions between objects. As a result, API documentation began to take the form of reference manuals, with detailed descriptions of each function, parameter, and return value. Meanwhile, API Technical Writers specializing in producing reference guides, tutorials, and sample code emerged. These writers must have a strong understanding of programming concepts, software development, and the specific API they are documenting. Moreover, they must be able to communicate complex technical information concisely so developers with varying levels of experience easily understand them.

API Technical Writing

Some of the common responsibilities of an API technical writer include:

  • Collaborating with developers and other stakeholders to understand the API’s functionality and requirements
  • Writing and organizing technical documentation that includes API reference guides, tutorials, and sample code
  • Ensuring that the documentation is accurate, complete, and up-to-date
  • Testing and verifying the API’s functionality to ensure that the documentation is accurate
  • Working with cross-functional teams to ensure that the documentation meets the needs of developers, product managers, and other stakeholders

With the increasing popularity of APIs, a variety of tools and services have emerged to help developers generate and manage API documentation. In recent years, there has been a growing focus on creating API documentation that is user-friendly and easy to understand. Many of these tools are designed to automate the documentation process, using machine-readable specifications such as OpenAPI (formerly Swagger) or RAML (RESTful API Modeling Language) to automatically generate documentation from code comments, annotations, or other sources.

API Documentation in Technical Writing
Credit: NicoElNino via Adobe Stock

Today, API documentation has become a vital component of software development. Many organizations invest significant resources in creating and maintaining high-quality documentation. The rise of open-source software and API marketplaces has also led to an increased emphasis on API discoverability. This value attached to such ease of use further underscores the importance of comprehensive and accessible API documentation.

Ongoing Evolution of API Documentation

The evolution of API documentation has been closely tied to the evolution of the internet and online technologies. As software development has become more global, API documentation has needed to adapt to meet the needs of developers around the world.

One of the most significant trends in the evolution of API documentation has been the move toward online documentation. In the past, the documentation was often provided in printed manuals that developers had to download and refer to offline. With the rise of the internet, developers have come to expect documentation that is available online and easily accessible anywhere.

The online documentation has several advantages over traditional printed documentation. For example, it can be updated more easily and frequently, ensuring that developers always have access to the latest information about an API. Online documentation can also be more interactive and dynamic, with features like live code samples, interactive tutorials, and search functionality that make it easier for developers to find the information they need.

New Approaches to API Documentation

Current API documentation practices are often inadequate, as they fail to provide sufficient information about how to use APIs and how they behave under different circumstances. Specifically, common problems with the documentation include missing or incomplete information, confusing or inconsistent terms, and insufficient examples.

Besides, researchers had been developing new approaches to providing high-quality API documentation. In particular, live API documentation automatically generate continuous updating of documentation for APIs. Real-time feedback improves developer productivity and reduces errors by providing up-to-date information about APIs and their usage. Most importantly, such a documentation system can leverage the aggregate experience of API users to reduce the difficulties that programmers have learning new APIs.

Other researchers had also proposed a system that pushes relevant API information to developers as they work. The system specifically monitors developers’ activities such as code edits and API calls. Afterward, this information would be used to identify relevant sections of the API documentation. Then, the corresponding content will be displayed to the developer in an unobtrusive manner, such as through a tooltip or a small pop-up window.

API Documentation Graphic

Some of the New Approaches for API Documentation Include:

  1. Interactive documentation: Interactive documentation makes it easier for developers to understand how to use an API. It may include live code samples, interactive tutorials, and other features that help developers experiment with an API in real time.
  2. API explorers: API explorers are user-friendly tools that allow programmers to examine an API’s features without writing any code. They may include live data previews, interactive documentation, etc. to aid in understanding an API’s operation.
  3. Developer portals: Developer portals are thorough internet sources that give developers all the information they need to use an API. Developer portals may offer tutorials, sample codes, SDKs, etc. to help create apps.
  4. Machine-readable documentation: this type of documentation is simpler to parse and comprehend because it employs structured data formats like JSON or YAML. It is possible to automatically produce machine-readable documentation from source code, which lessens the amount of manual labor needed to write and update documentation.
  5. API design-first documentation: this strategy emphasizes producing clear documentation before coding. It ensures that the documentation reflects the intended functions of the API.

API Documentation Toolkit

There are various tools available for creating API documentation. Here are some popular ones. However, none of the will beat the skill and concision of an API documentation suite written by a technical writer.

  1. Swagger
    An open-source toolset for documenting RESTful APIs. It includes a specification format called OpenAPI that is used to describe the API’s operations and data models. Swagger also provides a user-friendly interface for exploring and testing the API.
  2. OpenAPI
    A specification format for describing RESTful APIs. It allows developers to describe an API’s operations, parameters, and responses in a standardized format. The description can be used by tools like Swagger to generate documentation and code.
  3. API Blueprint
    A markdown-based language for describing RESTful APIs. It allows developers to describe an API’s resources, parameters, and responses in a simple and human-readable format. API Blueprint can be used with various tools to generate documentation and code.
  4. RESTful API Modeling Language (RAML)
    A specification format for describing RESTful APIs. It allows developers to describe an API’s resources, parameters, and responses in a structured format that can be used to generate documentation and code.
  5. Postman
    A toolset for building and testing APIs. It includes a user-friendly interface for creating API requests and responses, as well as a feature for generating documentation based on the API’s requests and responses.
  6. Stoplight
    An API design and documentation platform that includes a visual editor for designing APIs, a mocking service for testing APIs, and a documentation generator for creating API documentation.

API Documentation Plays a Key

In conclusion, API documentation plays a key role in software development, facilitating the smooth functioning of various applications. As software technology advances, the approach toward creating API documentation has shifted from traditional methods like text files and basic HTML pages to modern techniques such as online documentation. Technical writers are consistently adapting to new documentation production strategies to meet the needs of developers. The growth in popularity of APIs has given rise to innovative methods, such as live documentation and real-time systems that provide timely feedback. Despite these developments, the significance of API documentation in facilitating communication, data exchange, and collaboration between software applications remains undiminished. In fact, API documentation is more important than ever in today’s fast-paced environment, where efficient communication is vital for success.

How Can EDC Help With API Documentation?

Whether you need a single API documentation technical writer for a brief project or a team of consultants to produce a complete line of documentation, the quality of our work is guaranteed for you. Our clients work closely with an Engagement Manager from one of our 30 local offices for the entire length of your project at no additional cost. Contact us at (800) 221-0093 or sales@edc.us to get started.

Written by Julie Chow