Commercial HTTPS proxies that allows inline HTTP payload modification?

I need to modify the payload for a HTTP POST request to a particular HTTPS webapp.

I've managed to do to it using a short Python script in mitmproxy, just to test things.

However, I'm wondering which commercial MITM proxies allow you to modify HTTP request payloads inline?

A lot of products seem to have their documentation and help articles behind paywalls/subscription only, which is actually quite frustrating when you're trying to evaluate things like this 🙁.

PAN has an article on modifying headers but I don't see payloads mentioned.

"HTTP Header Insertion and Modification" https://docs.paloaltonetworks.com/pan-os/8-1/pan-os-new-features/app-id-features/http-header-insertion.html