# Swagger and OpenAPI ## Why is Documentation Important? * Without documentation, no one will know how to call your API * If no one calls your API, it has no reason to exist * If your API has no reason to exist, you will be unemployed * When you are unemployed, you will wish you had written documentation for your API ;-) ## What is Swagger? An open-source framework for designing and describing REST APIs. Equally suitable for both designing new APIs and documenting your existing APIs. A Swagger specification describes the API endpoint, available resources and operations that can be called against these resources. ### Why Swagger? * The simple YAML format is human-readable, machine-readable and self- explanatory * There is a variety of tools built around it that facilitate API development * Swagger `Codegen` can generate server code and client SDKs based on a Swagger specification * `Swagger UI` can render Swagger specifications to interactive API documentation, like the one at * These are just a few examples of how Swagger can help API developers ### API First Approach * Design the API First and generate a Mock * Use Python Library like `Connexion` to Implement * `Connexion` allows the code to comply with the API ! ### Problems with using External Documentation * A separate thing for developers to update * Too easy for developers to change the code and forget to change the documentation * Requires developers to look in a separate place for documentation instead of being in-line with the code ## What is SwaggerHub? SwaggerHub is an online platform where you can design your APIs and collaborate on them using Swagger – be it public APIs, internal private APIs or microservices The core principle behind Swagger and SwaggerHub is Design First, Code Later. That is, you start by laying out your API, its resources, operations and data models, and once the design is complete you implement the business logic Your API definitions are saved in the SwaggerHub cloud and can be synchronized with external systems like GitHub or Amazon API Gateway --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://notes.dizy.cc/devops/swagger-and-openapi.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.