For now you need to create your own OAuth Client ID to be able to use this extension. Getting a production enabled OAuth Client ID is complicated but is planned in the future.
⚠️ The following description can change over time. Make sure to obtain an OAuth key and not an API key!
You can search on Google or YouTube to get a better process description like e.g. this blog post.
Goto Google Developers Console
Make sure that you logged in with the Google Account which will be associated with your new OAuth key
Create a project and named it e.g. Raycast
This step take some seconds until the project is created.
Enable the Gmail API
Enable buttonEnable OAuth
OAuth consent screen on the left sideExternal and click CreateApp Name type RaycastUser Support Mail type your own email addressDeveloper Contact Info type your own email addressSave and ContinueTest Users and add the email address you wanna manage via RaycastCredentials on the left sideCreate Credentials on the top (blue text)OAuth client IDApplication Type choose iOSName type RaycastBundle ID type com.raycastCreateNow you should be able to manage your Gmail account with Raycast.