cURL Explained: What Is It and What Are the Alternatives?

Client Uniform Resource Locator (cURL) is a command-line tool that enables you to send requests using any network protocol. This way, cURL facilitates data transfer/exchange. It supports HTTP, HTTPS, POP3, POP3S, LDAP, LDAPS, DICT, FILE, FTP, FTPS, SMB, SMBS, SMTP, SMTPS, GOPHER, IMAP, IMAPS, MQTT, RTMP, RTMPS, RTSP, TFTP, TELNET, and more.

You can access cURL from the built-in terminal on your macOS, Windows (10 or higher), and Linux computer. In addition, the open-source cURL license allows developers to use elements of cURL in their proprietary or free software. This is why cURL is used to create numerous applications that connect to the internet. Such applications can be found in audio equipment, televisions, routers, cars, printers, smartphones, tablets, and more.

Uses of cURL

Using the predefined cURL commands, which are accessible by typing curl –help all commands on your terminal, you can perform numerous operations, including:

• Sending requests using a myriad of protocols
• Connecting to a URL via proxy (cURL with proxy)
• Following redirects
• Disabling buffering of the output stream
• Permitting insecure server connections even when the Secure Sockets Layer (SSL) is used
• Passing custom header(s) to the server
• Specifying the crypto engine that should be used
• Sending cookies from a string or file
• Performing HTTP authentication
• Verifying the status of the server certificate
• Stipulating the DNS server address(es) that should be used
• Sending mails to or from an address
• Sending the user agent name to the server

Shortcomings and Deficiencies of cURL

cURL has the following two deficiencies:

1. cURL is offered under a similar license to the MIT license

cURL is an open-source project whose license is inspired by, though not entirely identical to, the MIT license. Thus, if you create free MIT-licensed cURL-based software, another developer can take it and use it as a foundation for a commercial and proprietary application or plugin. If you are concerned about this fact, you can use the GNU General Public License (GPL), which guarantees the same free licensing terms for every user. A GPL-licensed tool cannot be used to create commercial software.

2. It is based on cURL commands

In order to use cURL in its basic command line-based format, you must have a good grasp of the curl commands. And although the curl –help all command enables you to access all the commands, it is still somewhat complicated, especially if your knowledge of HTTP and other network protocols is not extensive. 

3. cURL does not have a graphical user interface (GUI)

The complication highlighted in point 2 above is further exacerbated by the fact that cURL does not have a GUI. In this regard, users must interact with it solely via the command line unless they develop an interface that interacts with the tool.

Top 7 cURL Alternatives

cURL may not be everyone’s cup of tea in spite of or due to the deficiencies highlighted above. Fortunately, there are a few alternatives you can use, including:

1. Postman

Postman is an API platform that allows developers to design, build, test, and use APIs. It helps ease the API development lifecycle and enables teams to collaborate. Though Postman is a proprietary tool that is available at a fee, users can use an available free package.

2. Wget

GNU Wget is free software that is designed to retrieve files using the HTTP, HTTP, FTP, and FTPS protocols. Like cURL, it is a non-interactive command line tool. But it offers an advantage over cURL because it is distributed under the GNU GPL rather than the MIT license.

3.  HTTPie 

HTTPie is a powerful command-line tool that is designed for API testing. It achieves this by enabling users to send arbitrary HTTP requests using a simple syntax. But unlike cURL, which mainly uses the command line and displays the HTML responses in a black-and-white format, HTTPie displays a colorized and formatted output. 

4.  xh

xh is a free, open-source tool that is compatible with macOS, Windows, and Linux. It is primarily used to send HTTP requests. And like cURL, it is based on the command line. However, xh only supports the HTTP network protocol.

5. Curlie

Curlie combines the capabilities and power of cURL and the ease of use that HTTPie offers. This tool uses HTTPie’s interface and, therefore, supports colorized output. 

6. lftp

lftp is a command line-based file transfer tool that supports FTP, FTPS, HTTPS, HFTP, FISH, and SFTP. It also has a built-in BitTorrent client to facilitate torrent commands.

7. Hurl

Hurl is a command-line tool that sends/runs HTTP requests. It can fetch data using these requests as well as test HTTP sessions and XML/JSON APIs.

Conclusion

cURL is a command-line tool that facilitates data exchange between a device and a web server through a terminal. This solution is used in various instances, including utilizing curl with proxy to connect to a web server via a proxy server, following redirects, performing HTTP authentication, sending emails to and from an address, and more. By the way, Oxylabs wrote a blog post about how to use cURL with proxies, make sure to check it. 

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