Validating APIs
You can validate your API schema in Postman, and validate your elements (documentation, tests, mock servers, and monitors) against your schema. This helps keep your API well-defined and ensures that your elements are in sync with your schema. If there is a validation error on the schema or elements don't match it, Postman will present a list of issues that have been found, as well as fixes for these issues. You can then apply fixes to the API elements and revalidate them.
Validating schemas
Schema validation is available for OpenAPI 2.0, 3.0, and 3.1 and WSDL 1.1 and 2.0 schemas.
Postman indicates validation errors on your API schema as you edit it in the Definition tab on the API version page. Errors can include missing required fields, malformed field names, incorrect data types, incorrect nesting, or other API schema validation issues.
The pane below the schema editing area displays issues. You can hide and show the error view as you work.
Each error will indicate the type, the line on which it occurs, and details of the issue. You can also hover over the error inline in the editor to see information as you type.
Note that sometimes a single error in your schema will cause more than one issue to appear in the list. As you fix your errors you will see the validation issues disappear.
If there is an issue with your schema JSON or YAML syntax, you will see a warning. Look for errors indicated in the editor and hover over them for more detail. Postman will only be able to validate your schema elements if the JSON or YAML is itself well-formed.
If there are no errors, Postman will indicate in the lower pane that your schema is valid.
Validating elements
Element validation is available for OpenAPI 3.0 and WSDL 1.1 and 2.0 schemas.
You can compare your API schemas against documentation, mock servers, tests, and monitors associated with it to determine if the elements need changes to stay in sync. For example, if you add a new method to your API schema, validation will indicate you need to add the method to your associated documentation. Or when you add a new element to an API, you can run a validation to check the element against the current API schema for issues.
Each element has a Validate column next to where it's located in the API page. (Documentation and Mock servers are on the API Overview tab; tests are on the Test tab; monitors are on the Monitor tab.)
To validate a new element, select Validate in the validate column next to the element. To re-validate an element, select the status, then select Validate Again.
Once the validation is complete, a checkmark will appear next to the element if no issues have been found, or a warning message stating that issues are found. If there are issues, select the status, then select Review Issues to review them.
Validating requests
If you want your requests to be validated, your collection must be linked to an API.
A collection is linked to an API if you generate it from a schema or add it as a relation to an existing API.
Postman will validate a request when it's sent. If issues are found, you will see a warning message showing the number of issues next to the name of the request.
Validation is version-specific, and will be performed against the schema of the particular version of the API linked with the collection. If one version of a collection is linked to more than one version of an API, Postman will select the schema from the latest created version of API for validation.
Accessing issues
You can review the issues found during validation to fix issues in your collections or schemas.
If an issue arises when you run a request, select the warning message next to the name of the request (for example, 1 issue). This will open a panel on the right indicating detailed information about which component of the request is affected and what the issue itself is, and a direct link to the API against which the request is validated. Select the link to open the API within Postman.
You can select a specific issue to access the relevant request component.
If your issue relates to another element, open your API by selecting APIs in the app sidebar, then select an API version from the list. Open the tab containing the element you want to see issues for (either Overview, Test or Monitoring).
You will see a status indicating if issues have been found during validation next to the element. If there are issues, view them by selecting Issues found > View issues. This will take you to a page summarizing validation issues.
Updating API elements
The issue summary indicates the details of each issue and provides fixes you can automatically apply to the corresponding API element.
Understanding the issue summary
The validation summary lists all the issues found between the generated collection and the API schema. You can select suggested changes to make to the collection.
You can select the request name or the request element in the right sidebar to go directly to the corresponding issues.
The review contains details on what changes need to be made for the API element to be in sync with the schema again.
Applying changes to API elements
You can individually select the changes to be applied to the API element as you review them. Select the change you want to apply, then select the checkbox next to it. Repeat the same action for each change you would like to apply.
When you're done selecting the changes to apply, select Confirm Changes to Collection.
Alternatively, you can apply all changes by selecting Select all changes, then Confirm Changes to Collection.
You can access the updated API element by selecting View Updated Collection from the confirmation screen. If you didn't apply all changes, you can also review the remaining issues by selecting View Remaining Issues.
If you've been using this feature, the Postman team would like to hear from you! You can provide feedback on the community forum.
Next steps
In addition to keeping your API elements in sync with a schema, you can use reports to promote understanding of how your APIs are performing.
Last modified: 2022/04/22