Firstly there’s a way to not have a test and production url? If I’m testing a web page contact form then it’s a lot of work to change the url and republish just to do testing on n8n.
I think you cannot have only production url, but you can pin webhook input
About header (or other auth method), you can read more here but you just create credential, and set it to webhook, after this n8n will handle authentication (if passed correct then work otherwise return 403 error)
Actually, its not working . However, it might be a good start.
Keep in mind that testing the webhook with a response node works differently than in production; it doesnt respond the same way. It should work if your workflow performs an action, though.
Note that you will need to look at the executions because no data will appear in editor mode, which could be a hindrance. Hopefully, youll still find this useful.