httptoolkit-server VS mitmproxy

I'm the author. I'm not a Go developer though, can you give me an example I can reproduce for `go get` that doesn't work for you?

For the terminal, there's a few mechanisms, but environment variables are the catch-all there, yes (full list: https://github.com/httptoolkit/httptoolkit-server/blob/maste...). Those do work for most cases, but it is absolutely not a hard guarantee for applications that actively ignore standard proxy configuration (handling that is very hard, and definitely out of scope here).

Go does generally observes `http_proxy` correctly by default in other cases I've tested, so this vert simple code from the test suite is automatically intercepted for example: https://github.com/httptoolkit/httptoolkit-server/blob/maste.... Very happy to look into any failing cases you can share.

This statement gives a false sense of security. You can use a transparent proxy, like mitmproxy, to view HTTPS traffic - https://mitmproxy.org/. https://reedmideke.github.io/networking/2021/01/04/mitmproxy-openwrt.html

You'll need to install mitmproxy and set it up on your computer and iOS. I won't go into too much detail here on how to do this, but there are plenty of guides available. This is a pretty good one: https://nadav.ca/2021/02/26/inspecting-an-iphone-s-https-traffic/

TIL this goes back to 2006, how cool! We nowadays have a much simpler version as a mitmproxy example: https://github.com/mitmproxy/mitmproxy/blob/main/examples/ad.... Although it obviously does not work as well anymore with everything being HTTPS nowadays (unless you trust the cert of course). :)

Perhaps you could have your device use a proxy that can do the HTTPS unwrap for you? https://mitmproxy.org/ maybe?

A great way to test the effectiveness of a pinning implementation is by simulating an MITM attack. Tools like Mitmproxy or Wireshack allow us to create a test environment to monitor, intercept, and proxy network requests for a test host.