One of the most essential requirements in the API development phase is creating detailed documentation. The API documentation explains what the API methods do or how they are used. Thus, it serves as a guide or reference manual for other developers integrating the API in their apps. However, writing comprehensive and user-friendly API documentation manually is challenging. Moreover, it is extremely difficult to keep the documentation up-to-date. Fortunately, Swagger has made it easier for developers to document APIs. Developers and companies worldwide now use Swagger to document APIs, including tech giants like Google and Microsoft.
But what is swagger, and why do you need it for your project? This article will answer all these questions.
Table of Contents
What is Swagger?
Swagger is a framework that provides a contractual standard and set of open-source tools that help developers build Rest APIs. It provides convenience in API design, development, documentation and testing.
It provides a range of tools, including an editor for writing OpenAPI specifications, a code generator for creating server and client code from those specifications, and UIs for interacting with APIs.
Swagger basically allows developers to write API documentation according to OpenAPI standards, ensuring it meets the specifications. In other words, Swagger ensures you’ve included all the necessary information in the documentation that users will need.
The OpenAPI Specification (formerly called Swagger Specification) is essentially a standard for defining RESTful APIs. It provides a format for describing the structure of RESTful APIs, including:
- Endpoints
- Parameters
- Request and response bodies
- Authentication methods and more
Features of Swagger
Here are the prominent Swagger tools and features:
Swagger Editor
The Swagger Editor is a user-friendly web-based tool that enables developers to design and write API specifications using the OpenAPI Specification. It provides a clean and intuitive interface for defining endpoints, parameters, request and response bodies, authentication methods, and more. The editor also offers real-time validation and feedback. This makes it easy for developers to write accurate and compliant API specifications.
Swagger UI
Swagger UI is a tool for automatically generating interactive API documentation from OpenAPI Specification files. It renders detailed API documentation in a human-readable format, including examples and code samples for each endpoint and parameter.
Swagger Codegen
As the name implies, Swagger Codegen is a code generation tool that automates the process of generating server and client code from OpenAPI Specification files. It supports a wide range of programming languages and frameworks.
Why do API Developers Need Swagger?
Contractual Communication
An API enables two apps or software systems to communicate, interact, and exchange data. The most important stage of communication is the contract. For example, many people use the English contract to communicate among themselves. The rules are clear. The same goes for the communication between two computer systems.
Using the Swagger OpenAPI standard, we can share our APIs in a common language in a format that both humans and machines can understand. People can understand what the service context is by looking at your Open API contracts. In addition, we can generate client or server code for machines that comply with the contract rules. Supporting more than 40 language and application platforms, Swagger is a good platform choice in today’s API development.
Ease of Documenting APIs
Another crucial requirement in API development is API documentation. When you share your services privately or publicly with other developers, you should have clear documentation of what API methods do and how they work.
API documentation should answer the following questions:
- What is the API’s definition
- What does this service do
- What kind of operations does it contain
- What style should these operations be used
- What type of input and output parameters does the API use
Manually writing API documentation that answers all these questions is not only difficult, but it’s almost impossible to keep it up to date. Thus, it’s best to generate API documentation automatically.
Swagger can automatically generate documentation (based on the OpenAPI Specification) from service contracts held in YAML or JSON format. For instance, we can use Swagger UI, a user-friendly interface that renders the API documentation in a web browser. When provided with the OpenAPI Specification file, Swagger UI generates interactive documentation that allows users to explore and interact with the API endpoints directly from their browser.
Developers can view all endpoints, their corresponding HTTP methods, request parameters, response formats, and example requests/responses.
API Testing
Swagger is also helpful in API testing. For instance, developers can leverage Swagger UI to test API endpoints interactively directly from the documentation interface. They can send requests with various parameters and payloads and see the responses in real-time. This makes it easy to validate and verify the behavior of API endpoints and ensure that they meet the expected requirements.
Code Generation
Another prominent feature of Swagger is its ability to generate server and client code from API specifications. Developers can use the Swagger Editor to define their APIs. They can then use code generators to automatically generate server stubs in various programming languages and client libraries like JavaScript, Node.js, Python, and Java.
This significantly accelerates the development process and ensures consistency between the API definition and the implementation.
SDK Generation
Developers can also use Swagger/OpenAPI specifications to generate client SDKs in various programming languages automatically. This enables other developers/users to quickly integrate APIs into their applications without writing HTTP requests and handling responses manually.
Conclusion
Swagger is a highly preferred technology for API development. It is a framework for describing and documenting RESTful APIs according to OpenAPI specification. It allows developers to define the structure, endpoints, request/response formats, authentication methods, and other details of their APIs in a machine-readable format. Swagger is widely used to generate API documentation.
Because APIs are designed to be integrated into apps or software systems, it’s critical to ensure consumers can quickly implement and understand your API. For this reason, writing extensive documentation is essential. However, preparing documentation manually feels like a daunting task to most people. In addition, let’s think that a document has been created forcibly. Swagger enables developers to automatically generate API documentation based on the OpenAPI Specification.
FAQs
What is Swagger?
Swagger is essentially a framework that provides a contractual standard and set of open-source tools to help developers build Rest APIs. It provides convenience in API design, development, documentation and testing.
How to generate SDK using Swagger?
- Write OpenAPI specification
- Select and install a code generation or use Swagger Codegen
- Generate the SDK by providing your OpenAPI Specification file as input to the code generator
How does Swagger generate code?
You can use Swagger Codegen in your Swagger API project to generate code automatically. Swagger Codegen takes an OpenAPI Specification file as input and produces code in the target programming languages.
