Selenium

Selenium passes proxy settings to the browser as host:port only. Chrome and Firefox then show a native login dialog for authenticated proxies, which WebDriver cannot fill. Pick one of three approaches:

Approach	Credentials	Effort	Best for
A. IP whitelist	none in the browser	lowest	servers with a fixed public IP
B. selenium-wire	in Python code	low	Python projects, any number of proxies
C. Local forwarding proxy	in a sidecar process	medium	Java, C#, Selenium Grid, any language

Rotating residential needs credentials (targeting lives in the username), so use B or C for residential.

A. IP whitelist#

Add your server's public IP in Settings → Proxy access → IP whitelist (see IP whitelist), then pass host:port:

from selenium import webdriver

opts = webdriver.ChromeOptions()
opts.add_argument("--proxy-server=http://fr.mobile.gw.proxuno.com:10421")
driver = webdriver.Chrome(options=opts)
driver.get("https://api.ipify.org")
print(driver.find_element("tag name", "body").text)
driver.quit()

Firefox:

opts = webdriver.FirefoxOptions()
opts.set_preference("network.proxy.type", 1)
opts.set_preference("network.proxy.http", "fr.mobile.gw.proxuno.com")
opts.set_preference("network.proxy.http_port", 10421)
opts.set_preference("network.proxy.ssl", "fr.mobile.gw.proxuno.com")
opts.set_preference("network.proxy.ssl_port", 10421)
driver = webdriver.Firefox(options=opts)

B. selenium-wire (Python)#

selenium-wire runs a small proxy inside your Python process that adds the credentials upstream. The project is no longer actively maintained but remains widely used; pin its version.

pip install selenium-wire "blinker<1.8"

from seleniumwire import webdriver

options = {
    "proxy": {
        "http": "http://m_k3v9q2xa:[email protected]:10421",
        "https": "http://m_k3v9q2xa:[email protected]:10421",
        "no_proxy": "localhost,127.0.0.1",
    }
}
driver = webdriver.Chrome(seleniumwire_options=options)
driver.get("https://api.ipify.org")

selenium-wire intercepts TLS with its own certificate; Chrome accepts it automatically. Some sites detect the altered TLS fingerprint — if that matters, use approach C.

C. Local forwarding proxy#

Run a tiny proxy on the same machine that forwards to Proxuno with credentials, and point the browser at it without credentials. gost does this in one command:

gost -L http://127.0.0.1:3128 -F "http://m_k3v9q2xa:[email protected]:10421"

Then, in any language:

ChromeOptions options = new ChromeOptions();
options.addArguments("--proxy-server=http://127.0.0.1:3128");
WebDriver driver = new ChromeDriver(options);
driver.get("https://api.ipify.org");

The TLS session stays end-to-end between the browser and the site (the forwarder only relays CONNECT tunnels), so fingerprints are unchanged. Run one forwarder per proxy on different local ports for parallel sessions.

Rotation with Selenium#

Rotate between tests, not in the middle of a page load. From Python:

import requests, time

def rotate(link: str) -> str:
    r = requests.get(link, timeout=45)
    if r.status_code == 429:
        time.sleep(int(r.headers.get("Retry-After", 10)))
        return rotate(link)
    r.raise_for_status()
    return r.json()["ip"]

Start a new WebDriver session (or clear cookies) after a rotation so the site does not tie the old session to the new IP.

Troubleshooting#

Symptom	Cause
A login pop-up appears and the test hangs	Credentials were not supplied — use one of the approaches above.
`ERR_PROXY_CONNECTION_FAILED`	Wrong host or port, or the forwarder (approach C) is not running.
Works locally, fails in CI	CI runners use a different egress IP than the whitelisted one.