Clients are welcome to use their own reverse proxy solution. Most firewall appliances can provide this functionality.
Our recommended best practice is a network layer proxy secured with TLS client certificates. Be careful if you're using a layer 7 proxy or API management solution since it may block some of the requests and introduce additional latency.
If you're using your own reverse proxy, ensure that your proxy does not attempt to validate the XML since some responses passing through the system may not conform to verifiable standards.