# curl with HTTP and SOCKS5 proxies: copy-paste examples

> curl proxy examples: -x and -U, SOCKS5 with --socks5-hostname, sticky sessions, CONNECT status and timing with -w, curl.exe on Windows.

- URL: https://crawlrelay.com/docs/curl/
- Last updated: 2026-10-13
- Publisher: CrawlRelay (https://crawlrelay.com)

curl is the fastest way to test credentials, targeting and timing before you touch your scraper. Every command below runs as it is once you replace USERNAME and PASSWORD.

**Quick answer — How do I use a proxy with curl?**

Use `curl -x http://USERNAME:PASSWORD@gw.crawlrelay.com:7777 https://api.ipify.org` for the HTTP proxy, or `--socks5-hostname gw.crawlrelay.com:7778` with `-U USERNAME:PASSWORD` for SOCKS5. **CrawlRelay** residential proxies take the country and a sticky session in the username, such as `USERNAME-country-de-session-t1-ttl-10`. From $0.50/GB. Paid in crypto, with no KYC.

## curl flags you need

| Attribute | Value |
| --- | --- |
| `-x` / `--proxy` | Proxy URL: `http://host:port`, credentials optional inside it |
| `-U` / `--proxy-user` | Proxy credentials as `USERNAME:PASSWORD`, kept out of the URL |
| `--socks5-hostname` | SOCKS5 proxy with DNS resolved at the exit |
| `-v` | Shows the CONNECT exchange and the proxy's status line |
| `-w` | Prints timing, size and `%{http_connect}`, the proxy's CONNECT status |
| `--max-time`, `--connect-timeout` | Total and connection time limits, in seconds |

## What are the basic proxy commands?

Each of these prints the exit IP the website sees.

*HTTP proxy, rotating, then targeted and sticky*

```bash
# Rotating exit, any country
curl -x http://gw.crawlrelay.com:7777 -U USERNAME:PASSWORD https://api.ipify.org

# Country and city (city availability varies)
curl -x http://gw.crawlrelay.com:7777 -U USERNAME-country-us-city-chicago:PASSWORD https://api.ipify.org

# Sticky: run it twice, the IP stays the same for up to 10 minutes (it can change earlier)
curl -x http://gw.crawlrelay.com:7777 -U USERNAME-country-de-session-t1-ttl-10:PASSWORD https://api.ipify.org

# SOCKS5, DNS resolved at the exit
curl --socks5-hostname gw.crawlrelay.com:7778 -U USERNAME-country-gb:PASSWORD https://api.ipify.org
```

## How do I debug a proxy connection with curl?

Run with `-v` and read the lines around `CONNECT`. A working tunnel shows `HTTP/1.1 200 Connection established`, then the TLS handshake with the website. Any other status on that line came from the proxy: 407 means credentials, 502 or 504 means the exit or the target. The `-w` format below prints the same information in one line, which is handy in loops and CI checks.

*Verbose CONNECT and a one-line timing report*

```bash
# Full exchange, including the proxy's answer to CONNECT
curl -v -x http://gw.crawlrelay.com:7777 -U USERNAME:PASSWORD https://example.com/ -o /dev/null

# One line: proxy CONNECT status, HTTP status, compressed bytes and timings
curl -s --compressed -o /dev/null -x http://gw.crawlrelay.com:7777 -U USERNAME-country-us:PASSWORD \
  -w 'connect=%{http_connect} http=%{http_code} bytes=%{size_download} tcp=%{time_connect}s tls=%{time_appconnect}s ttfb=%{time_starttransfer}s total=%{time_total}s\n' \
  https://example.com/
```

## How do I check that rotation and sessions work?

Request the IP several times. Without a session ID, every run is a new connection and usually shows a different IP. With a session ID, the IP should stay the same until the TTL ends, though it can change earlier.

*Rotation vs sticky in a shell loop*

```bash
echo "rotating:"
for i in 1 2 3 4 5; do
  curl -s -x http://gw.crawlrelay.com:7777 -U USERNAME-country-us:PASSWORD https://api.ipify.org; echo
done

echo "sticky:"
for i in 1 2 3 4 5; do
  curl -s -x http://gw.crawlrelay.com:7777 -U USERNAME-country-us-session-loop1-ttl-5:PASSWORD https://api.ipify.org; echo
done
```

## How do I use curl with a proxy on Windows?

Call `curl.exe`, not `curl`. In Windows PowerShell 5.1, `curl` is an alias for `Invoke-WebRequest`, which does not understand `-x` or `-U`. Windows 10 and 11 ship the real curl as `curl.exe`. In PowerShell, quote arguments that contain special characters, and write a literal `$` in a password inside single quotes.

*PowerShell*

```powershell
curl.exe -x http://gw.crawlrelay.com:7777 -U 'USERNAME-country-fr:PASSWORD' https://api.ipify.org
```

## How do I set the proxy once for every command?

curl reads the `https_proxy` and `http_proxy` environment variables, and many other tools read them too. Set them for a shell session, and use `NO_PROXY` for hosts that must not go through the proxy, such as your own API. Avoid putting the password in a variable that is exported to every child process on a shared machine.

*Environment variables (bash, zsh)*

```bash
export https_proxy="http://USERNAME-country-us:PASSWORD@gw.crawlrelay.com:7777"
export http_proxy="$https_proxy"
export NO_PROXY="localhost,127.0.0.1,.internal.example"

curl https://api.ipify.org   # now uses the proxy
unset https_proxy http_proxy # back to direct
```

## curl and proxies: questions

### What is the difference between --socks5 and --socks5-hostname?

With `--socks5`, curl resolves the hostname on your machine and sends the IP address to the proxy. With `--socks5-hostname`, it sends the hostname and the proxy side resolves it. Use `--socks5-hostname` for scraping so DNS answers match the exit country, and so your local resolver does not see the domains you fetch.

### Why does curl say 'CONNECT tunnel failed, response 407'?

The proxy rejected the credentials, or received none. Check the username and password, and URL-encode special characters if they are inside the `-x` URL, or pass them with `-U` instead. The [407 page](https://crawlrelay.com/docs/errors/407-proxy-authentication-required/) lists the other causes.

### How do I see how many bytes a page costs through the proxy?

Add `--compressed -o /dev/null -w '%{size_download}\n'`. `--compressed` makes curl ask for gzip or brotli like your scraper does, and `%{size_download}` then counts the compressed bytes that crossed the wire. Without it, the server sends the page uncompressed and the figure can be several times higher. Run it on a handful of real pages to estimate your traffic per 1,000 pages.

### Can curl use HTTP/2 or HTTP/3 through the proxy?

HTTP/2 works inside the CONNECT tunnel when the website supports it, because the tunnel carries TLS end to end. HTTP/3 runs over UDP, which a CONNECT tunnel through an HTTP proxy does not carry, so use HTTP/2 or HTTP/1.1 through the gateway.

**Test your targets from the command line** $1.50 for 1 GB, enough for thousands of curl tests. [Choose 1 GB](https://crawlrelay.com/app/checkout/?plan=res-1&product=residential&lang=en) · [Error reference](https://crawlrelay.com/docs/errors/)

---

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