Proxy speed: how we measure latency and why ping lies

When someone asks "how fast is this proxy?" they usually mean one thing but need three. Conflating them is why a proxy that "pings fast" still feels slow in real use.

• Latency is the round-trip delay for a small request — how long before anything comes back. It dominates the feel of interactive work and many small requests, like API calls or page navigation.
• Throughput is how much data per second the proxy can move once a transfer is going. It dominates large downloads and heavy scraping, and a low-latency proxy can still have poor throughput.
• Time-to-first-byte (TTFB) is the whole chain: DNS, the connection handshake, the proxy relaying your request, the destination thinking, and the first byte arriving. It is the closest single number to "how the request actually felt."

For most proxy work the number that matters is latency and TTFB, because you are making many requests, not one giant download. That is the column we surface on the free proxy list, and it is what the scripts below measure.

The instinct is to ping a proxy and trust the millisecond figure. It is misleading for several concrete reasons. A ping uses ICMP, a different protocol from the TCP and TLS your actual traffic uses — networks routinely prioritise, deprioritise or entirely block ICMP, so the ping number reflects neither. Ping also measures the hop to the proxy, not the full path through it to your real destination, which is what you care about. And it completely ignores the costs that dominate real requests: the TCP handshake, TLS negotiation, DNS resolution and the time the destination itself takes to respond.

The honest way to measure a proxy is to measure a real request through it, timing the connect and first-byte stages the way curl reports them. That captures the handshake, the relay and the destination — everything ping throws away. It is exactly how the latency figures on our list are produced, which is the point of publishing a transparent methodology rather than a marketing number.

To compare proxies honestly, hold the variables steady. Test every proxy against the same target and from the same network, run each one several times and report the median rather than the luckiest sample, and always measure a baseline with no proxy so you can attribute the added latency to the proxy rather than to your own connection or the destination. Distance is physics: a proxy geographically far from you or from the target will always add latency no tunnel can remove, so factor location in rather than blaming the proxy.

This is the same discipline behind s4m's numbers. Authenticated datacenter proxies are built for consistent, low-latency performance, and the free-list latency column is generated from real timed requests, not ICMP. Want a single proxy checked instantly? Use the proxy checker; want to validate a whole list including speed, see how to check proxy validity.