Discord Integration is currently only available in certain Hosted CTFd tiers and CTFd Enterprise
As part of the Webhooks integration, CTFd supports Discord webhooks without any kind of intermediary server or developer setup.
Creating Discord Webhook
Create a Discord webhook by following the instructions available here
Open the CTFd Webhooks Plugin
Click on the Discord tab
Enter the Discord webhook URL and click the "Validate & Add" button. The webhook URL should look like
Select the events that will trigger the webhook