Notification via Webhook (or API request)

E-mail is only desired for external communication in our company. Internal communication and the submission of tasks are done via a personal dashboard of an employee in another solution. The goal is to let employees work with as few tools as possible.
So we would also like to receive notifications to employees not via email, but via API or webhook.
Either as a webhook to an address to be defined, or by request.
The message would also only have to contain the information that is already available in the e-mail:

e-mail of the recipient,
subject
copy text
call-to-action URL to the personal page
if applicable, the name

Optional: individual deactivation of the sending of e-mails per user.