How to test a mobile proxy with cURL

Updated 5 October 2026

Commands for checking, timing and rotating a T-Proxy UK mobile proxy from the command line, and what the common errors mean.

Your first request

cURL is already installed on macOS, Linux and Windows 10/11. Pass the proxy with -x and the login with -U:

$ curl -x HOST:HTTP_PORT -U USERNAME:PASSWORD https://api.ipify.org

It prints the IP address that websites see. You can also put everything in one proxy URL, which is the form most other tools accept:

$ curl -x http://USERNAME:PASSWORD@HOST:HTTP_PORT https://api.ipify.org

SOCKS5

Use your SOCKS5 port with the socks5h:// scheme. With the h, the proxy looks up domain names itself, so DNS goes over the UK mobile connection too. Plain socks5:// resolves names on your own computer first.

$ curl -x socks5h://USERNAME:PASSWORD@HOST:SOCKS_PORT https://api.ipify.org

Check the IP address

# IPv4 address only
$ curl -x HOST:HTTP_PORT -U USERNAME:PASSWORD https://api.ipify.org

# the address most sites will see: IPv6 if the proxy prefers it
$ curl -x HOST:HTTP_PORT -U USERNAME:PASSWORD https://api64.ipify.org

# response headers only, e.g. to check a site loads
$ curl -I -x HOST:HTTP_PORT -U USERNAME:PASSWORD https://www.bbc.co.uk/

Proxies on SIMs with IPv6 use it first by default. If you need IPv4 everywhere, change the Default IP setting on the proxy page.

Time a request and test speed

-w prints timings once the request finishes. When you use a proxy, connect is the time to reach our server and tls is the time until the HTTPS handshake with the site, through the mobile connection, is done:

$ curl -s -o /dev/null -x HOST:HTTP_PORT -U USERNAME:PASSWORD \
    -w 'connect %{time_connect}s  tls %{time_appconnect}s  first byte %{time_starttransfer}s  total %{time_total}s\n' \
    https://www.google.co.uk/

For a rough download speed, fetch a 25 MB test file and print the average speed in bytes per second (divide by 125,000 for Mbit/s):

$ curl -s -o /dev/null -x HOST:HTTP_PORT -U USERNAME:PASSWORD \
    -w '%{speed_download} bytes/s\n' \
    'https://speed.cloudflare.com/__down?bytes=25000000'

Mobile speeds vary with signal and how busy the local cell is, so run it a few times. 5G plans give more headroom than 4G.

Rotate the IP

Each proxy has its own Rotation URL on its page. Request it to get a new IP address on the same modem. No login is needed, and the URL stays the same for the life of the proxy. Prefix it with time to see how long the rotation took:

$ time curl -s "YOUR_ROTATION_URL"
{"result": "success", ...}

# then check the new address
$ curl -x HOST:HTTP_PORT -U USERNAME:PASSWORD https://api.ipify.org

• The reply comes back once the modem has its new address, usually in well under a minute and occasionally up to about two. The proxy doesn’t answer during that time.
• A "result": "fail" reply says why, for example when a rotation is requested too soon after the last one. Leave at least a minute between rotations.
• Keep the Rotation URL private: anyone who has it can rotate your proxy.

Use environment variables

cURL, and many other command-line tools, pick up a proxy from environment variables, so you don’t have to repeat -x. On macOS and Linux:

$ export https_proxy="http://USERNAME:PASSWORD@HOST:HTTP_PORT"
$ export http_proxy="$https_proxy"
$ curl https://api.ipify.org

Note http_proxy must be lower case; https_proxy works in either case. Run unset http_proxy https_proxy to stop using the proxy.

On Windows

Windows 10 and 11 include the real cURL as curl.exe. In Windows PowerShell, plain curl is a shortcut to a different command (Invoke-WebRequest) with other options, so type the .exe:

PS> curl.exe -x HOST:HTTP_PORT -U USERNAME:PASSWORD https://api.ipify.org

In Command Prompt, plain curl works. Use double quotes, not single quotes, around URLs and -w formats there, and replace -o /dev/null with -o NUL.

Common errors

Questions

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