smee-client VS smee.io

Well, that will require a change in the smee-client as well. So maybe a follow-up?

Neat stuff - certainly this problem crops up quite a lot where an internal server needs to get GitHub webhook data.

In the past, I've had good luck using a webhook proxy. I've mostly just used https://smee.io/ which is simple and lightweight although seems to be mostly abandonware at this point. I dockerized it so that it could be used in a Kubernetes cluster, which was very useful for my GitHub Actions build cluster: https://github.com/ethomson/smee-client

There's also Hookdeck, which I haven't used in production, but have played around with, and it seems conceptually the same, but can be made more Enterprisey. Whether that's a bug or a feature is probably up to you.

Using the same probot/smee-client shipped by Probot we divert the webhook URL to one on localhost for the development application, and for the production application we will enter a custom route.

My recommended starting point is to fork/clone the smee.io repo and get it working. And by working, I don't mean deploying it, but being able to build and run it locally to a point where you can place a break point in the code and have it pause there. This is necessary in order to customize any code. I actually had some issues doing that with the main branch as it was in commit 3a01759.