currently there are no webhook events for reacting to a comment/PR/Issue.
Would be nice to have this. I'd like to build a sort of merge bot who decides based on reactions and it would be much nicer If I could avoid querying the API in various time intervals to see what the latest reaction count is.
There was a feature request open for this, but it is only in the google cache-the link doesn't work anymore: https://platform.github.community/t/webhook-for-reaction-creation-on-issue-comment/1779
Thanks for this feedback! We're always working to improve GitHub and the GitHub Community Forum, and we consider every suggestion we receive. I've logged your feature request in our internal feature request list. Though I can't guarantee anything or share a timeline for this, I can tell you that it's been shared with the appropriate teams for consideration.