The extension: required parameter flags a view as requiring extension, which means that the view cannot be used on its own. The contents and settings of the view will only be used when the view is extended using the extends parameter in another view.
A view with extension: required is not visible to users on its own; it is intended only to act as a starting point to be extended by other views.
The extension parameter accepts only the value required. If you don't want to require extension for a view, leave out the extension parameter entirely.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14 UTC."],[],[],null,["# extension (for views)\n\n\u003cbr /\u003e\n\n\u003e This page refers to the `extension` parameter that is part of a [view](/looker/docs/2512/reference/param-view-view).\n\u003e\n\u003e `extension` can also be used as part of an Explore, described on the [`extension` (for Explores)](/looker/docs/2512/reference/param-explore-extension) parameter documentation page.\n\u003e\n\u003e `extension` can also be used as part of a LookML dashboard, described on the [Dashboard parameters](/looker/docs/2512/reference/param-lookml-dashboard#extension) documentation page.\n\nUsage\n-----\n\n```\nview: view_name {\n extension: required\n}\n```\n\nDefinition\n----------\n\nThe `extension: required` parameter flags a view as requiring extension, which means that the view cannot be used on its own. The contents and settings of the view will only be used when the view is extended using the [`extends`](/looker/docs/2512/reference/param-view-extends) parameter in another view.\n\nA view with `extension: required` is not visible to users on its own; it is intended only to act as a starting point to be extended by other views.\n\nThe `extension` parameter accepts only the value `required`. If you don't want to require extension for a view, leave out the `extension` parameter entirely.\n\nSee [Reusing code with extends](/looker/docs/2512/reusing-code-with-extends) for more information on using `extends` for LookML objects.\n\nExample\n-------\n\nThe following `looker_events` view has the `extension: required` parameter, so the view itself won't be visible to users:\n\nFile: `events.view` \n\n view: looker_events {\n extension: required\n sql_table_name: looker_db.events ;;\n # The normal contents of the view follow\n }\n\nIf we want to make use of the `looker_events` view, we can create another view that extends it, like this:\n\nFile: `new_events.view` \n\n include: \"events.view\"\n view: name_of_the_new_view {\n extends: [looker_events]\n\n measure: additional_measure {\n type: count\n }\n # Additional things you want to add or change\n }"]]