`redirect_uri`|`string` | The URL in your application where users will be sent after authorization. See details below about[redirect urls](#redirect-urls).

`scope`|`string` | A space delimited list of[scopes](#scopes). If not provided,`scope` defaults to an empty list for users that have not authorized any scopes for the application. For users who have authorized scopes for the application, the user won't be shown the OAuth authorization page with the list of scopes. Instead, this step of the flow will automatically complete with the set of scopes the user has authorized for the application. For example, if a user has already performed the web flow twice and has authorized one token with`user` scope and another token with`repo` scope, a third web flow that does not provide a`scope` will receive a token with`user` and`repo` scope.

`state`|`string` | An unguessable random string. It is used to protect against cross-site request forgery attacks.

`allow_signup`|`string` | Whether or not unauthenticated users will be offered an option to sign up for GitHub during the OAuth flow. The default is`true`. Use`false` in the case that a policy prohibits signups.

`allow_signup`|`boolean` | Whether or not unauthenticated users will be offered an option to sign up for GitHub during the OAuth flow. The default is`true`. Use`false` in the case that a policy prohibits signups.