Do you do any sort of rate-limiting to stop people/bots from hammering it (accidentally or otherwise)? Or do you just let it fall over under load.
If you want to hit it hard, or you just want to avoid any risk of limits in future, it's a one-liner to host it yourself with Docker: `docker run --rm -it -p 3000:3000 httptoolkit/testserver`, then open http://example.localhost:3000/. Advanced config options for CAs etc are in the GitHub README.