API / Swagger Interview questions

What is Swagger?

Swagger is a set of open-source tools built around describing, documenting, and testing REST APIs using a standardized, machine-readable format — originally its own specification, which later became the foundation for the OpenAPI Specification.

The Swagger toolset today centers on three main tools: Swagger Editor for writing and validating an API definition, Swagger UI for rendering that definition as interactive, browsable documentation, and Swagger Codegen for generating client SDKs or server stubs directly from the definition.

Because the underlying definition is a structured document (YAML or JSON) rather than free-form prose, it can be validated, versioned in source control, and fed into other tooling automatically, which is what separates Swagger/OpenAPI-based documentation from a hand-maintained wiki page that inevitably drifts out of sync with the actual API.

Take quiz

What format is a Swagger/OpenAPI API definition typically written in? YAML or JSON

✓ Correct! Well done.

Only compiled binary files

✗ Try again if not.

Only Microsoft Word documents

✗ Try again if not.

What does Swagger UI do with an API definition? Encrypts the entire API

✗ Try again if not.

Renders it as interactive, browsable documentation

✓ Correct! Well done.

Deletes it after one use

✗ Try again if not.

More Related questions...

What is Swagger? What is the purpose of Swagger? What is the OpenAPI Specification? What is the difference between Swagger and OpenAPI? What are the key components of Swagger? What is Swagger UI? What is Swagger Editor? What is Swagger Codegen? Define paths in an OpenAPI document? What are operations in OpenAPI? What is a schema in OpenAPI? What are the supported formats for writing an OpenAPI document? What is the purpose of the info object in OpenAPI? What are tags used for in Swagger? List the HTTP methods supported in OpenAPI operations? What is a parameter in OpenAPI, and what are its types? What is a response object in OpenAPI? Describe the components section in OpenAPI 3.0? What is $ref used for in OpenAPI documents? How do you use Swagger annotations in a Java Spring Boot application? What is the difference between OpenAPI 2.0 (Swagger) and OpenAPI 3.0? What is the difference between OpenAPI 3.0 and OpenAPI 3.1? Why is contract-first API design preferred over code-first in some teams? How does Swagger support security schemes like OAuth2 and API keys? What is the difference between springfox and springdoc-openapi? How do you document request and response examples in OpenAPI? Explain how Swagger Codegen generates client SDKs from an OpenAPI spec? What is the difference between path parameters and query parameters? How do you handle polymorphism and discriminators in OpenAPI schemas? Explain the lifecycle of validating an OpenAPI document with a linter like Spectral? When should you use the allOf, oneOf, and anyOf keywords in OpenAPI schemas? How do you version a REST API documented with Swagger? What happens when you click "Try it out" in Swagger UI? How do you split a large OpenAPI specification across multiple files? Explain the internal working of Swagger UI's rendering process? How do you mock an API server using an OpenAPI specification? What is the difference between Swagger and Postman? How do you deprecate an API operation in OpenAPI? Explain the execution flow of generating server stubs from an OpenAPI document? What is the difference between Swagger 2.0's definitions and OpenAPI 3.0's components/schemas? How does content negotiation work in OpenAPI, using the content field? Why doesn't OpenAPI natively describe webhooks before version 3.1? How do you handle authentication in Swagger UI for testing secured endpoints? What is the difference between OpenAPI Generator and the legacy Swagger Codegen? Explain how to enforce validation constraints in an OpenAPI schema? How do you convert a Swagger 2.0 document to OpenAPI 3.0? What is the role of the servers object in OpenAPI 3.0? Explain the internal working of $ref resolution across multiple OpenAPI files? How do you implement contract testing using an OpenAPI specification? Explain the execution flow of API documentation generation in a CI/CD pipeline using Swagger/OpenAPI tooling?

Show more question and Answers...

Comments & Discussions

Web services 115 Microservices 41 GraphQL Interview Questions 32 Docker Interview questions 14 Docker Interview questions contd. Vault interview questions 6 Kubernetes Interview questions 14 Rancher Interview questions 1 Kaniko Interview Questions APIGEE Interview questions Microservices Design Patterns Interview Questions 45 OpenAPI Interview questions APIGEE Gateway Interview Questions 40 Swagger Interview questions 50

Recently added questions

What are the supported formats for writing an OpenAPI document? What is $ref used for in OpenAPI documents? What is Swagger Editor? What is a schema in OpenAPI? List the HTTP methods supported in OpenAPI operations? Describe the components section in OpenAPI 3.0? What is the OpenAPI Specification? What is Swagger UI? Define paths in an OpenAPI document? What are operations in OpenAPI? What is the purpose of the info object in OpenAPI? What are tags used for in Swagger? What is a parameter in OpenAPI, and what are its types? What is a response object in OpenAPI? What is Swagger? What is the purpose of Swagger? What is the difference between Swagger and OpenAPI? What are the key components of Swagger? What is Swagger Codegen? How do you use Swagger annotations in a Java Spring Boot application?

	Interviews Questions Java Spring Hibernate DevOps Testing API BigData Web Erlang AI Database Integration Cloud Python Scala Tools Golang SAP	About Javapedia.net Javapedia.net is for Java and J2EE developers, technologist and college students who prepare of interview. Also this site includes many practical examples. This site is developed using J2EE technologies by Steve Antony, a senior Developer/lead at one of the logistics based company. Follow Javapedia updates
	contact: javatutorials2016[at]gmail[dot]com
Kindly consider donating for maintaining this website. Thanks.
	Copyright © 2026, javapedia.net, all rights reserved. Privacy policy.