If you have the API details for the Sendgrid Web API then yes. There is
the webhook mechanism for Alertmanager which allows you to send alerts
to anything you want, via a small service/lambda that translates from
the webhook API to the destination API. There are numerous such services
that are available already (e.g. for sending alerts to MS Teams), but
I'm not sure if a Sendgrid one has already been written.
--
Stuart Clark