As part of a deployment to production, all Apex tests are run in the production organization. If the organization contains a large number of Apex tests, the execution of all tests can be time-consuming and can delay your deployment. To reduce deployment time to production, you can perform a quick deployment by skipping the execution of all tests. Quick deployments are available only for validations with test runs that have passed in the last four days (96 hours) and that meet the code coverage requirements: the overall code coverage in the organization must be at least 75%, and Apex triggers must have some coverage.
To perform a quick deployment, first run a validation-only deployment with Apex test execution on the set of components that you need to deploy to production. If your validation succeeds and qualifies for a quick deployment, you can start a quick deployment by clicking Quick Deploy next to your validation in the Deployment Status page or in the validation’s detail page. This button appears only for qualifying validations.
You can start a quick deployment only through the Salesforce user interface. Quick Deploy is available for change sets and Metadata API-based deployments that appear in the user interface.