I have no idea because I have never worked with SendGrid. Throttling is always a possibility when working with cloud services and the usual technique is to build in microdelays so that a process doesn’t become a candidate for throttling. I don’t think webhooks will be phased out because they are used in so many places.

We have noticed that the SendGrid API’s has a maximum limitation of 1000 items per query when we are gathering reporting information. We are tracking volume, bounces, blocks etc. Some of our API keys send more than 1000 emails a day. They also throttle the queries so that our reporting is slower by virtue of explicit delays added to avoid the limits. SendGrid themselves suggested Webhooks as a solution for gathering real time data. IT actually seems like a good solution. I have also noticed that webhooks are available for all kinds of triggering available for Azure, GitHub and other systems for real time triggering and reporting. The coding associated with Webhooks is much more involved than API programing. I am wondering if I have found a solution or if I am going down a rabbit hole. If these hooks and triggers are going to be around and represent a natural next step to reporting and event responses, then they are worthy of time and energy they will take. However, if this is considered an antiquated technology or Microsoft is going to be phasing out support for them, then it’s not worth the effort to develop skills in this area.
You always seem to know the mindset at Microsoft. Any insights in this area are always helpful.

What do you want to use webhooks for?