You can access your notification settings at https://www.hackster.io/users/notifications/edit. Email notifications will be sent to the email address associated with your Hackster account, while web notifications will appear in the bell icon next to your user profile.
To update contest notification settings, scroll to the bottom of the page to Contest settings. You can turn off email or web notifications by unchecking the boxes next to each option.
If you want to stop notifications from a specific contest, expand the table by clicking "Update settings for contests you're participating in" You'll see each contest you are currently registered for and can turn off email or web notifications for specific contests.