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# Run a collection with a mock

You can redirect collection requests to a [mock](/docs/design-apis/mock-apis/local-mock-servers) using the **Mock** tab in the Collection Runner. For each base URL in the collection, you can select a different mock. This lets you test how your service behaves without calling real services.

## Select a mock for a collection run

Run a collection with a mock to test your service against mock responses. When you start the run, Postman redirects requests matching the selected base URL to the mock.

1. Click ![Items icon](https://assets.postman.com/postman-docs/aether-icons/v12/icon-descriptive-items-stroke.svg#icon) **Items** in the left sidebar.
2. Click **Collections** and select the collection you want to run.
3. Click ![Run icon](https://assets.postman.com/postman-docs/aether-icons/v12/action-run-stroke.svg#icon) **Run**.
4. Select **Functional**, then select **Local**, **Schedule**, or **Postman CLI**.
5. Configure the collection run settings as needed.
6. Click the **Mock** tab.
7. For each base URL in the collection, use the **Select mock** dropdown list to choose a mock. To create a new mock, select ![Add icon](https://assets.postman.com/postman-docs/aether-icons/v12/icon-action-add-stroke.svg#icon) **Create mock** from the dropdown list. Postman identifies all requests using that base URL and uses them in the mock's [implementation](/docs/design-apis/mock-apis/local-mock-servers#customize-your-mock).
8. (Optional) Next to each mock dropdown list, select a scenario with specific request handling code, endpoints, and conditions. To learn more about scenarios, see [Manage scenarios in a mock](/docs/design-apis/mock-apis/local-mock-servers#manage-scenarios-in-a-mock).
9. Click **Start run** or **Schedule Run**. To run the collection with the Postman CLI, copy the generated commands.

You can also use the `--use-mock` option with the [`postman collection run` command](/docs/postman-cli/postman-cli-collections/#postman-collection-run) to redirect requests to a mock directly from the Postman CLI.

## View mock events

After the collection run completes, you can view the **Mock events** tab in the run results. The **Mock events** tab shows events associated with the mock, including applied scenarios, response code, and tests that ran.

Learn more about [viewing collection run results](/docs/tests-and-scripts/running-collections/intro-to-collection-runs#debug-run-results).