How to design & test APIs with OpenAPI & Swagger | What's changed in 3.1 & 3.2

Outdated API docs and last-minute bugs cost teams time and trust. Learn how the OpenAPI Specification help you document, govern, and test your APIs from design to deployment – all inside SmartBear Swagger.

SmartBear's Yousaf Nabi, Developer Advocate, and Chris Armstrong, Manager of Developer Relations, explain why API documentation drifts out of sync and walk through what's changed between OpenAPI 3.0, 3.1, and 3.2. After covering a brief history of Swagger and the OpenAPI specification, they demo the full API workflow across Swagger.

What you'll learn:

• How to design APIs in Swagger Studio
• How to discover and align APIs with Swagger Portal and Swagger Explore
• How to enforce shared contracts with Swagger Contract Testing
• How to validate API behavior with Swagger Functional Testing
• How Swagger Catalog keeps your API portfolio visible and governed

Chapters:

00:00 Introduction

00:18 What you'll learn

00:51 What is an API?

02:27 Why API documentation matters

03:12 Swagger, OpenAPI, and reducing API drift

05:17 OpenAPI 3.1 & 3.2 updates

14:50 Swagger Editor and AsyncAPI

17:36 Building an API lifecycle with Swagger

22:55 Creating an API with AI

27:18 Publishing API documentation & developer portals

30:12 Mock servers and API exploration

33:48 Contract testing and compatibility checks

38:43 Understanding Swagger Contract Testing

41:54 Writing consumer contract tests

44:31 AI-assisted contract testing with MCP

46:04 Generating and reviewing contract tests

50:29 Contract testing in action

54:17 Functional API testing

57:47 Running tests in CI/CD

59:20 AI-powered API documentation
01:00:52 Key takeaways