Change record status: 
Project: 
Introduced in branch: 
11.4.x
Introduced in version: 
11.4.0
Description: 

JSON:API had a soft dependency on justinrainbow/json-schema; validation of the response was performed automatically if the dependency was enabled via \Drupal\jsonapi\EventSubscriber\ResourceResponseValidator. This has a sizable performance hit.

In Drupal 11.4 and 12.0 this dependency will be shipped as a runtime dependency in order to assist SDC and Canvas with additional validation.

JSON:API is considered stable and has an extensive suite of tests. As a result, JSON:API validation has been moved to a test-only module. If your tests were relying on this validation, you can re-enable it by installing the jsonapi_response_validator module.

Impacts: 
Module developers