What is Swagger

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Swagger framework
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Swagger is a framework which helps in API documentation generation, build, management and client stubs creation. Swagger allows us to define the API structure automatically so that 2 machines can communicate easily. 

Developing APIs that all love is a very tricky process. As more organizations and development teams are building and leveraging APIs, there’s an increased specialize in integrating with APIs that are easy to figure with, and performance as intended. Quality and simple consumption are the most important factors that affect API adoption, and developers got to take them under consideration when building new APIs.

The Swagger tools reinvented the way APIs are being designed and built. But because the landscape changes, and developers are expected to enhance the quality and readability of the APIs they deliver, the necessity for an easy API testing and documentation generation tool on the fly became apparent to us.

Swagger is a framework which consists of multiple open source, free and few commercial tools for implementing OpenAPI specifications. Swagger helps in different processes of Rest APIs like build, design, documentation and consumer clients creation.

Swagger framework consists of multiple tools, few of them are explained below:

Swagger Editor

Swagger Editor is a browser-based editor in which you can write OpenAPI specs. Swagger editor lets you edit OpenAPI specifications in YAML format inside the browser. You can preview the changes at real-time. You can try it here.

Swagger UI

Swagger UI renders OpenAPI specifications as an interactive API documentation. Swagger UI is basically a GUI which consists of HTML, CSS and Javascript assets. It reads OpenAPI specification’s json file and renders the interactive page in the browser.

Swagger Codegen

Swagger codegen generates the server stubs and all required client libraries from an OpenAPI specification using OpenAPI specification.

Swagger Parser

Swagger parser parses Swagger specs in JSON or YAML format, its a standalone library for parsing OpenAPI definitions in Java

Swagger Core

Swagger Core is basically a Java implementation of the OpenAPI Specifications. 

Swagger Inspector 

Swagger Inspector enables you to automatically generate the OpenAPI file from any end point you provide. Within a few clicks, Swagger Inspector can generate your OpenAPI documentation and save a lot of valuable development time.


SwaggerHub is a platform for integrated API development that uses all the core features of the open source Swagger framework, along with additional advanced features to document,  build, deploy and manage your APIs.

SwaggerHub is basically a collaborative platform with its help we can define our APIs via OpenAPI specifications and manage APIs throughout their lifecycle. SwaggerHub is built by the same people which are behind the open-source Swagger tools. SwaggerHub integrates the core Swagger tools (Codegen, Editor, UI, Validator) into a single platform which helps to coordinate the complete API’s lifecycle.

SwaggerHub can help us to do number of tasks:

  • Defines the APIs in the OpenAPI format.
  • Hosts all your API definitions in a single location.
  • Saves the common API components (such as data models and responses) in domains and references those from API definitions.
  • Better collaboration on API definitions with your team.
  • Helps in generation of server side and client side code and pushes it to Git servers.
  • Enables us to share the APIs privately and publicly.
  • Provides the support for management of multiple API versions.

What Is OpenAPI?

OpenAPI Specification (earlier known as Swagger Specification) is an API description format for your REST APIs. An OpenAPI file enables you 

  • to describe your entire API, including available endpoints and operations on each endpoint with any HTTP method type. 
  • Listing of all Input and output parameters for each operation
  • Authentication mode if available
  • Contact information, terms of use, license and other information.
  • API specifications can be in JSON or YAML. The format is very easy to read and learn for humans as well as machines. 

Why Use OpenAPI?

The ability of an API to describe its own structure is the root of all the awesomeness. Once API is written, the OpenAPI specification and Swagger tools both can drive the API development further in multiple ways:

  • Design-first: You can use Swagger Codegen to generate a server stub for required API. The only thing you need to do is to implement the server logic – and your API will be ready to go live.
  • You can use Swagger Codegen to generate client libraries for your API in over 40 languages.
  • You can use Swagger UI to generate interactive API documentation web page that let you to try out the API calls directly in the browser.
  • You can use the API specification to connect API-related tools to your API. For example, import the specification into SoapUI to create the automated tests for the API.

What is swagger used for

Swagger is a vast framework for designing your APIs using a common language and enabling the development process across the whole API lifecycle, including documentation, design, deployment and testing.

Why documentation matters

Good documentation accelerates development and consumption, and reduces the cash and time that might rather be spent answering support calls. Documentation is a component of the general user experience, and is one among the most important factors for increased API growth and usage.

Challenges of API documentation

APIs, like numerous other products, tend to evolve rapidly during the development & release cycles. The process of updating and maintaining the updated documentation for end users as well as for developers, is very difficult. It is often very true if you’re using static documents, like a pdf, to supply documentation to your end consumers. The other issue is facilitating interaction between multiple web services. Applications are made from multiple services that constantly communicate and interact with one another .

As RESTful services grow in number, so do the programming languages that are wont to implement them, making it harder for them to speak . The  API documentation is often thought of as the interface for consuming an API, and as such, must facilitate interaction between these different web services. Regular API interfaces, be it text based documentation, or others like Javadocs style, don’t allow them to speak with one another . These challenges, alongside other pain points of  APIs, inspired the Swagger Specification.

In the next section, we’ll take a better check out how the OpenAPI Specification (formerly referred to as the Swagger Specification) can help address your documentation challenges.

Why use OpenAPI for API documentation

The Swagger Specification, which was renamed to the OpenAPI Specification (OAS), after the Swagger team joined SmartBear and therefore the specification was donated to the OpenAPI Initiative in 2015, has become the de factor standard for outlining RESTful APIs.

OAS defines an API’s contract, allowing all the API’s stakeholders, be it your development team, or your end consumers, to know what the API does and interact with its various resources, without integrating it into their own application. This contract is human readable and language agnostic, allowing both machines and humans to understand and parse .

The OAS contract describes what the API does, it’s request parameters and response objects, all with none indication of code implementation. Web services defined with OAS can communicate with each other irrespective of the language they’re created, since OAS is language agnostic and computer readable.


Overall we can say Swagger is an awesome framework, it supports support to multiple languages like Java, PHP, .NET etc and gives such a relief to developer from maintaining the updated API documentation and tring the API responses from browser directly.