If you want to do intercept something manually, there's general instructions under the 'Anything' interception option. In short:
- Set the proxy on the device to point at your machine's local IP, usually on port 8000 (active port is shown under the 'Anything' option)
- Trust the generated MITM certificate on your device, so you can intercept HTTPS too (path to the certificate also shown under 'Anything').
Fundamentally, HTTP Toolkit, Charles & Fiddler are all HTTP & HTTPS proxies, so they all allow intercepting the same things, it's just a matter of how easy the setup process is.
I know it isn't exactly what you're doing, but you might want to look at nogotofail on the Android side. It has all the per-app goodness baked in, and you could probably borrow its approach.
If you want to do intercept something manually, there's general instructions under the 'Anything' interception option. In short:
- Set the proxy on the device to point at your machine's local IP, usually on port 8000 (active port is shown under the 'Anything' option)
- Trust the generated MITM certificate on your device, so you can intercept HTTPS too (path to the certificate also shown under 'Anything').
Fundamentally, HTTP Toolkit, Charles & Fiddler are all HTTP & HTTPS proxies, so they all allow intercepting the same things, it's just a matter of how easy the setup process is.