cURL proxy – what is it and how to use guide

cURL proxy is a term you have undoubtedly encountered If you are a web developer or a web scraper. Using several protocols, you can send or receive data from a server by using the command-line program cURL. For testing APIs, downloading files, or web crawling, you can use cURL. But did you know that cURL works with proxies as well? 

In this article, we’ll define a cURL proxy, discuss when you might need one, and go through how to set it up. Additionally, we will contrast various proxy types and provide some real-world applications for cURL proxies.

What is a cURL proxy

A cURL proxy is a proxy server that you can use with cURL to hide your IP address, bypass geo-restrictions, or access blocked websites. You forward your requests and responses through a proxy server, an intermediary between your device and the target server. 

Using a proxy server, you can alter your IP address and give the impression that you are browsing from another location. You can access geo-restricted content, evade IP prohibitions, or scrape information from websites that forbid bots.

Different proxy protocols, including HTTP, HTTPS, SOCKS4, SOCKS4A, SOCKS5, and SOCKS5_HOSTNAME, are supported by cURL. The cURL command allows you to specify the proxy protocol, proxy address, and port number. For instance:

curl –proxy http://proxy_address:port_number http://example.com

This command will send a GET request to http://example.com using the HTTP proxy specified in the –proxy option.

 

cURL alternatives and why should you use cURL with proxies

There are other methods for transferring data over the internet besides cURL. Other additional options include Wget, Postman, and Python requests. Nevertheless, cURL has a few benefits that make it a preferred choice for web developers and web scrapers:

  • cURL is cross-platform and works on Windows, Linux, Mac OS, and other operating systems.
  • cURL supports many protocols, such as HTTP, HTTPS, FTP, FTPS, SFTP, SCP, TELNET, LDAP, POP3, IMAP, SMTP, RTMP, RTSP, and more.
  • cURL has many options and features that allow you to customize your requests and responses. For example, you can set headers, cookies, user agents, timeouts, redirects, authentication methods, SSL certificates, and more.
  • cURL is fast and reliable. It can handle multiple concurrent connections and resume interrupted transfers.

You can further improve the performance and functionality of cURL by using proxies. With cURL proxy cURL, you can:

Hide your IP address and protect your privacy. Proxies can mask your IP address and prevent websites from tracking your online activity or identifying your location.

Bypass geo-restrictions and access blocked websites. You can use proxies to access stuff blocked in your area or nation. For instance, you can access news websites that are restricted by your government or watch Netflix from other countries by using proxies.

Scrape data from websites without getting blocked. When attempting to scrape data from websites that forbid bots, proxies can assist you in evading IP bans or captchas. You can more effectively scrape data by employing residential proxies, which use actual IP addresses of household devices, or by switching proxies frequently.

 

Configuring a cURL proxy

You need a proxy server that supports the protocol you want to use with cURL to use a cURL proxy. Additionally, you must be aware of the proxy IP and port number. If the proxy requires authentication, you may need a username and a password.

Using the –proxy option in the cURL command, you can configure a cURL proxy after you have this information. The syntax of the –proxy option is as follows:

–proxy [protocol://][user:password@]proxyhost[:port]

For example:

curl –proxy http://user:password@proxy_address:port_number http://example.com

This command will send a GET request to http://example.com using the HTTP proxy specified in the –proxy option with authentication.

 

You can also set the proxy protocol separately by using the –proxytunnel option for HTTPS proxies or the –socks5 option for SOCKS5 proxies. For example:

curl –proxytunnel –proxy user:password@proxy_address:port_number https://example.com

This command will send a GET request to https://example.com using the HTTPS proxy specified in the –proxy option with authentication and tunneling.

 

curl –socks5 user:password@proxy_address:port_number http://example.com

This command will send a GET request to http://example.com using the SOCKS5 proxy specified in the –socks5 option with authentication.

 

Proxy Types: Choosing the Right Fit for a cURL Proxy

To configure and use a cURL proxy, you can use a variety of proxy protocols, including HTTP, HTTPS, SOCKS4, SOCKS4A, SOCKS5, and SOCKS5_HOSTNAME. Each proxy protocol offers pros and cons depending on your use case and requirements. The following are some things to consider while selecting the best proxy protocol for a cURL proxy:

  • Compatibility: Different websites and applications work better with some proxy protocols than others. For instance, websites and web servers support HTTP proxies more frequently than SOCKS proxies. Instead of only supporting HTTP or HTTPS traffic, SOCKS proxies are more adaptable and can handle any communication. So, you should utilize SOCKS proxies if you want to use cURL with protocols other than HTTP or HTTPS, such FTP or SMTP.
  • Security: Different proxy protocols offer different levels of security. For instance, HTTPS proxies, as opposed to HTTP proxies, encrypt the traffic between your device and the proxy server. However, HTTPS proxies do not encrypt the connection to the destination server. They only do so up until the proxy server. Therefore, you should use HTTPS or SOCKS5 proxies with SSL tunneling to utilize cURL with secure websites that require SSL certificates, like https://example.com.
  • Performance: Different proxy protocols have different speeds. Because they do not alter or interpret the traffic, SOCKS proxies, for instance, are quicker than HTTP proxies. They act as a packet forwarder between your device and the destination server. However, because SOCKS proxies do not compress or cache the data, they could also use up more bandwidth than HTTP proxies. So, you must utilize SOCKS proxies to use cURL with big files or streaming video.

Practical Examples: cURL Proxies actual use cases

To utilize cURL proxies in realistic situations, here are some real-world examples of cURL commands using various proxy protocols and settings:

  1. Download a file from a website using an HTTP cURL proxy:

curl –proxy http://proxy_address:port_number -O http://example.com/file.zip

This command will download the file.zip from http://example.com using the HTTP proxy specified in the –proxy option and save it to the current directory with the same name.

 

  1. Test an API using an HTTPS cURL proxy with authentication:

curl –proxytunnel –proxy user:password@proxy_address:port_number -H “Content-Type: application/json” -X POST -d ‘{“key”:”value”}’ https://api.example.com

This command will send a POST request to https://api.example.com using the HTTPS proxy specified in the –proxy option with authentication and tunneling. It will also set the Content-Type header to application/json and send the data {“key”:”value”} in the request body.

 

  1. Scrape data from a website using a SOCKS5 cURL proxy with rotation:

curl –socks5 user:password@proxy_address:port_number http://example.com

This command will send a GET request to http://example.com using the SOCKS5 proxy specified in the –socks5 option with authentication. If you have multiple proxies in a list or a pool, you can rotate them by using a bash script or a tool like ProxyChains.

 

Conclusion

Using several protocols, you can transport data to or from a server using the robust utility known as cURL. Using proxies, you can increase your privacy, get around geo-restrictions, or scrape data from websites without detected cURL. We described what a cURL proxy is when you might need one and how to configure it in this blog post. 

Additionally, we contrasted various types of proxies for cURL and provided some real-world applications for cURL proxies.

This tutorial has clarified how to use cURL with proxies. Please share your thoughts or questions with us in the comments section below.