--- title: About the setup URL intro: 'You can specify a URL that users will be redirected to after they install a {% data variables.product.prodname_github_app %}.' versions: fpt: '*' ghes: '*' ghec: '*' topics: - GitHub Apps shortTitle: Setup URL redirect_from: - /apps/creating-github-apps/setting-up-a-github-app/about-the-setup-url --- When you register a {% data variables.product.prodname_github_app %}, you can specify a setup URL. When users install your {% data variables.product.prodname_github_app %}, they are redirected to the setup URL. If additional setup is required after installation, you can use this URL to tell users what steps to take next. If you specify a setup URL, you can also select **Redirect on update** to specify that users should be redirected to the setup URL after they update an installation. An update includes adding or removing access to a repository for an installation. > [!WARNING] > When {% data variables.product.company_short %} redirects users to the setup URL, it includes an `installation_id` query parameter. Bad actors can hit this URL with a spoofed `installation_id`. Therefore, you should not rely on the validity of the `installation_id` parameter. Instead, you should generate a user access token for the user who installed the {% data variables.product.prodname_github_app %} and then check that the installation is associated with that user. For more information, see [AUTOTITLE](/apps/creating-github-apps/authenticating-with-a-github-app/generating-a-user-access-token-for-a-github-app). {% ifversion fpt or ghec %} Although the setup URL is optional during {% data variables.product.prodname_github_app %} registration, it is required if you want to allow users to purchase your app in {% data variables.product.prodname_marketplace %}. For more information, see [AUTOTITLE](/apps/publishing-apps-to-github-marketplace/using-the-github-marketplace-api-in-your-app/handling-new-purchases-and-free-trials). {% endif %} The setup URL is different from the callback URL. Users are redirected to the setup URL after they install a {% data variables.product.prodname_github_app %}. Users are redirected to the callback URL when they authorize a {% data variables.product.prodname_github_app %} via the web application flow. For more information, see [AUTOTITLE](/apps/creating-github-apps/setting-up-a-github-app/about-the-user-authorization-callback-url). For more information about registering a {% data variables.product.prodname_github_app %}, see [AUTOTITLE](/apps/creating-github-apps/setting-up-a-github-app/creating-a-github-app). For more information about modifying a {% data variables.product.prodname_github_app %} registration, see [AUTOTITLE](/apps/maintaining-github-apps/modifying-a-github-app).