How to write useful API documentation

Well-crafted API documentation is crucial for software engineers. It simplifies integration, troubleshoots issues, and saves time. In this blog post, we'll explore the role of API documentation, discuss its essential elements, cover best practices, introduce helpful tools, and provide a real-world example of a well-documented API. By the end, you'll have a comprehensive understanding of creating informative API documentation that allows a streamlined integration.

Why API documentation matters

API documentation is one of the most important aspects of software development. For starters, it helps new team members get up to speed quickly, understanding the project and how to contribute more effectively. When issues arise, as they inevitably will, well-organized documentation is a go-to resource for troubleshooting. You can find out what's supposed to happen, identify the problem, and sort it out more efficiently. Plus, detailed documentation lays the groundwork for better code quality by offering clear guidelines and examples.

Essential elements of good API documentation

Overview and getting-started guide

The Overview serves as an introduction to your API, providing context for its intended purpose. It may briefly describe the API's functionality, its intended use cases, and any limitations or prerequisites. The Getting-Started Guide, usually a sub-section within the Overview, offers a quick tutorial to help developers make their first API call. This hands-on experience can greatly enhance confidence and understanding.

Authentication and authorization

Every API that requires restricted access must have a section dedicated to explaining its authentication methods. Whether you are using API keys, OAuth, or any other method, this section should provide a clear step-by-step guide on how developers can authenticate themselves to make authorized API calls. The more detailed and well-explained this section is, the fewer questions developers will have regarding unauthorized errors.

Endpoint descriptions

Whether you're working with SOAP actions, RESTful endpoints, GraphQL operations, or gRPC methods, this section forms the backbone of your API documentation. In REST, as an example, this would typically involve outlining each endpoint along with its associated HTTP methods (GET, POST, PUT, DELETE, etc.), required parameters, and their functionalities. For GraphQL, you'd describe the available queries, mutations, and subscriptions, as well as the types and fields involved.

Regardless of the API type, the goal here is to offer a clear, concise guide on how to interact with each operation or endpoint. This often involves specifying parameters, providing example requests and responses, and explaining any related elements, such as headers or metadata.

Example of a REST API endpoint description.

Error handling

Effective API documentation should include a rigorously structured section that enumerates the possible error codes and associated messages one might encounter while interacting with the API. Each error code should be accompanied by a precise description that elaborates on the cause of the error. Additionally, it can be helpful to add recommended actions for resolution.

By integrating an "Error Codes and Messages" section into your API documentation, you improve the debugging process for developers, enhancing their experience and encouraging continued interaction with the API.

Rate limiting and quotas

If your API has limitations on the number of calls that can be made within a given time frame, this should be clearly documented. Information on rate limiting and quotas is essential for developers to design their applications in a way that avoids hitting these limits and effectively handles their applications when they do.

Sample code and libraries

Providing code samples in multiple programming languages can greatly reduce the learning curve and speed up the integration process. Developers can often copy-paste these samples into their code and modify them as needed.  Examples serve as practical illustrations and give developers a clear idea of how the API behaves in real-world scenarios. Additionally, developers can use cURL commands to quickly test API endpoints directly from their command-line interface.

Example of Twitter API’s Tools and Libraries.

As you can see in the example, Twitter offers a range of tools for developers. SDKs, no-code platforms, command-line interfaces, and more – they've got it covered. It's clear they want to make API integration as smooth as possible. This thoughtful approach greatly simplifies the onboarding process for developers, allowing them to easily integrate and use the API in their preferred programming language.

Change log and versioning

APIs are not static; they evolve over time. A change log keeps a historical record of all updates, modifications, and deprecations. It serves as a reference to understand how the API has changed, allowing developers to adapt their code accordingly.

Example of a changelog.

Best practices for API documentation

Clarity and simplicity

When it comes to API documentation, less jargon and more clarity go a long way. The goal is to make it easy for someone to integrate with your API. A straightforward explanation helps developers get the job done without having to decode complex terms.


Keep things consistent in your API documentation. Use the same format and structure throughout, whether it's for endpoint descriptions, request and response examples, or error codes. Consistency makes your documentation easier to navigate and understand.


Let's face it, reading documentation isn't the most exciting task. But what if you could try out API calls right there on the page? Including interactive examples not only keeps users engaged but also provides immediate feedback and validation.

Regular updates

An out-of-date doc is like an expired map; it's not much help. Technology changes, new features get added, and bugs get fixed. Make sure to regularly update your documentation to reflect these changes. Updated documentation avoids confusion, reduces troubleshooting time, and improves the overall user experience.

Effective search

Navigating extensive documentation can be challenging. Incorporating a responsive and accurate search feature addresses that challenge, allowing developers to swiftly jump to relevant sections. This not only saves time but also reduces frustration. A well-implemented search increases the overall usability of your documentation, enhancing user experience.


In the API documentation, there are some helpful tools that can make the process smoother.


Postman automatically generates documentation for every collection you create. The documentation includes all of the requests in your collection, along with examples, authorization details, and example code.


Swagger gives you a solid framework for documenting RESTful APIs with options for auto-generating code snippets.


Stripe's API documentation not only provides comprehensive information but also offers interactive pages and examples that make it easy for developers to understand and test their API. The documentation excels in user-friendliness and ease of navigation, setting a high standard for the industry.

One of the standout features of Stripe's API documentation is its attention to detail and meticulousness. It covers various endpoints and functionalities, ensuring that developers have all the necessary information to integrate Stripe's services seamlessly. The documentation goes beyond just listing available endpoints by providing clear and concise examples, making it easier for developers to understand how to use each API call effectively. This approach not only enhances developers' understanding but also allows them to test the API in real-time.

Furthermore, Stripe's documentation includes detailed explanations of response formats and possible error codes. This helps developers handle any issues that may arise during the integration process. Additionally, Stripe regularly updates its API documentation, ensuring that developers always have access to accurate and relevant information.

Overall, Stripe's API documentation stands out for its interactivity, clear examples, and ease of testing. It is a top choice for developers seeking reliable and well-documented APIs.

Final thoughts

Good API documentation directly impacts the developer experience. It's not just about listing endpoints or parameters, but ensuring developers can integrate effectively and with ease. Quality documentation removes roadblocks and guesswork, making a developer's job simpler and more efficient.

I hope this blog post made it clear how vital good API documentation is for developers. It's all about streamlining their work and making integration simpler.  If you want to enhance the developer experience, start with clear and concise API documentation.

André Penafort
Full-Stack Developer