How do I test whether a proxy is working correctly

Work through these in order. Each step rules out one layer, so you stop at the first failure instead of guessing.

1. Can you reach the proxy at all

curl -x http://USER:PASS@PROXY_IP:PORT -I https://example.com

A response means the proxy is reachable and your credentials work. 407 means authentication — see How do I handle a 407 error message. A connection refused or timeout means the address, port or your firewall is wrong.

2. Is your traffic actually going through it

curl -x http://USER:PASS@PROXY_IP:PORT https://api.ipify.org

The address returned must be the proxy's, not yours. If it is yours, your client is ignoring the proxy setting.

3. Is the location right

Look up the returned IP with any geolocation API. Databases disagree by a city or two; a wrong country is a real problem worth raising with support.

4. Are your DNS lookups leaking

With SOCKS5, make sure hostnames are resolved remotely rather than locally, or your resolver still sees every domain you visit.

5. Does the target itself respond

Only now try your actual target. If steps 1–4 passed and the target does not, the issue is between you and that site — see How to Fix Proxies Blocked Issue.

Testing at scale

Loop your whole list and record status and latency for each. How to test proxies in the Linux command-line interface has a shell version, and How to test the proxies using Python 3 a scripted one.

If a proxy fails step 1 or 2 consistently, that is ours to fix — open a ticket with the IP, the timestamp and the exact command.