HTTP vs HTTPS vs SOCKS5 proxies
Proxies differ in what they understand and how much they reveal. The three you'll meet most often are HTTP, HTTPS (CONNECT) and SOCKS5.
HTTP proxy
Speaks HTTP and forwards your requests. Because it sees the request, it can add headers such as
Via or X-Forwarded-For — which is exactly what lets a checker grade its
anonymity. Best for plain web traffic.
HTTPS / CONNECT proxy
An HTTP proxy that also supports the CONNECT method, opening an opaque TCP tunnel
(used for HTTPS). Because the tunnel is opaque, the proxy can't read or modify your request, so it
generally looks “elite”. Best for TLS traffic.
SOCKS5 proxy
A lower-level proxy that tunnels arbitrary TCP (and UDP) without understanding the application protocol. Flexible and protocol-agnostic, with optional username/password auth. Best when you need more than HTTP, or want a clean tunnel.
Which should you pick?
For web scraping over HTTPS, a CONNECT or SOCKS5 proxy is typical. For header-level testing or plain HTTP, an HTTP proxy is fine. The checker auto-detects the protocol, so when in doubt, paste and let it resolve.