You can use wireshark, a proxy like tinyproxy or squid or a debugging tool in a browser, chrome has it integrated, Firefox might have it also or it as a plugin called live http header.
Wireshark gets all packets it can even get request from other computers on the same network. You can use filters like http.request.method == "GET" or http.request.method == "POST" It gets the information by packet, a request could be longer than a packet, but not likely to happen. You can also ask on https://ask.wireshark.org. you could also use another packet sniffer like tcp dump.
To get all request from your computer with a proxie you will most likely have to configure it transparent and log all requests.
Debugging tools in browsers get only requests from one page, at least in chrome.