Postman API Builder Now Validates OpenAPI Definitions in Real Time


Since joining the OpenAPI Initiative (OAI) this summer, Postman has made a wave of incremental improvements to make our platform experience more seamless when it comes to using the OpenAPI Specification (OAS). For example, as of Postman v7.29, you can now validate your OpenAPI definitions in the Postman API Builder. This feature expands the API design-time capabilities of the API Builder, providing real-time feedback while you edit—so your definitions remain compliant with the OpenAPI Specification 3.0. Teams can now design APIs that are consistent across the full API lifecycle.

While editing your OpenAPI definitions in Postman, you will now see a new schema validation UI pane at the bottom of the editor. This pane provides instant validation feedback as you work with each API in your personal or team workspace. Now, if you make a typo or add any property that is not a valid part of the OpenAPI Specification, you will see alerts detailing the type of issue, the line where it exists, and the validation error returned:

Postman API Builder schema validation pane returns feedback on OpenAPI definitions

The information refreshes as you type, and a red x mark will display next to each line that contains a validation error (as shown in the top left of the above screenshot). Once you’ve cleaned up all validation errors, the header at the top of the validation pane will display “Schema validated” with a green check mark as confirmation:

Postman API Builder validates OpenAPI definitions

While editing the OpenAPI definitions for each API, you can expand or hide the schema validation pane as you work. You can choose to fix validation errors as you go, or do them all at once when you’re done editing.

The schema validation for OpenAPI provides you with real-time feedback so that you can confidently assemble an OpenAPI definition that will work in other systems, services, and open source tooling. This expansion of the Postman API Builder helps ensure more consistency and compliance when delivering APIs.

Since the OpenAPI Specification is the primary contract for defining what each API does for many Postman users, we are committed to delivering time-saving features that leverage the specification benefits that support API designers in delivering high-quality, well-designed APIs that meet the needs of the enterprise.

What do you think about this topic? Tell us in a comment below.


Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

1 thought on “Postman API Builder Now Validates OpenAPI Definitions in Real Time


    Thanks so much for this feature!

    Are there any plans to improve readability when dealing with large openAPI specifications? When i’m in the define tab for postman it’s difficult to navigate large specifications. My current spec is almost 8,000 lines and not close to being finished. The only way i know how to navigate in postman is to use search or scroll and scan.

    When working in my project from the code base, i have parts of the spec separated into folders so I can easily jump to sections from a folder and easily re-use code by importing modal definitions, etc. Since that’s faster and easier to keep organized when building a large spec, I build and then parse everything into a single file, then import that file into postman.

    It would be cool if postman was setup to make building large api’s in a modular fashion easier instead of wrestling with one large file