Apps & extensions

How to use proxies with cURL

cURL takes a proxy with the -x flag and credentials with -U, which makes it the fastest way to confirm that a proxy, its credentials and its geo-targeting all work before wiring them into anything larger.

Recommended for cURL

Residential proxies — cURL is mostly used here for verification, and the residential gateway is where targeting and rotation options are worth checking.

See residential proxies

Setup

1
Send a request through the proxy
Use -x for the proxy and -U for the credentials. Replace PROXY_HOST, PROXY_PORT, USERNAME and PASSWORD with the endpoint and credentials shown in your seamless dashboard.
```
curl -x http://PROXY_HOST:PROXY_PORT -U USERNAME:PASSWORD https://api.ipify.org?format=json
```
2
Or put credentials in the URL
A single combined flag is more convenient in scripts and environment variables.
```
curl -x http://USERNAME:PASSWORD@PROXY_HOST:PROXY_PORT https://example.com
```
3
Use SOCKS5
Switch protocol with the scheme. Use socks5h rather than socks5 so DNS is resolved at the proxy instead of locally, which avoids leaking the hostnames you look up.
```
curl -x socks5h://USERNAME:PASSWORD@PROXY_HOST:PROXY_PORT https://example.com
```

Check geo-targeting and timing

Confirm the exit country is what you asked for, and measure where the time actually goes.

# Which country did we exit from?
curl -x http://USERNAME:PASSWORD@PROXY_HOST:PROXY_PORT https://ipinfo.io/json

# Where is the latency?
curl -x http://USERNAME:PASSWORD@PROXY_HOST:PROXY_PORT \
  -o /dev/null -s \
  -w "connect: %{time_connect}s  ttfb: %{time_starttransfer}s  total: %{time_total}s\n" \
  https://example.com

cURL proxy FAQ

How do I use a proxy with cURL?

Pass the proxy with -x http://host:port and the credentials with -U username:password, or combine both as -x http://username:password@host:port. The same syntax works for SOCKS5 by changing the scheme.

What is the difference between socks5 and socks5h in cURL?

With socks5, cURL resolves the hostname locally and sends the resulting IP to the proxy. With socks5h, the proxy performs the DNS lookup. socks5h is normally what you want, because it prevents your local resolver from seeing which hosts you are visiting.

How do I check which IP a proxy is exiting from?

Request an IP echo service through the proxy, for example curl -x http://user:pass@host:port https://ipinfo.io/json. The address and country it returns are what the target site will see.