Tech blog and developer tools
cURL (short for "Client URL") is a command-line tool for transferring data using various network protocols. It was first released in 1997 by Swedish developer Daniel Stenberg, who still maintains it today. cURL is installed by default on macOS, most Linux distributions, and Windows 10+, making it one of the most universally available developer tools in existence.
While modern tools like Postman, Insomnia, and Bruno provide beautiful graphical interfaces for API testing, cURL remains the go-to for quick one-off requests, shell scripts, and CI/CD pipelines. When someone shares an API example in documentation, it is almost always a cURL command because it is universally understood and can be run immediately in any terminal.
Fun fact: cURL is used in virtually every internet-connected device. It is embedded in cars, TVs, routers, printers, phones, tablets, and even Mars rovers. Daniel Stenberg estimates cURL runs on over 10 billion installations worldwide. In 2020, he received a Polhem Prize, one of Sweden's most prestigious technology awards, for his work on cURL.
While both are command-line download tools, cURL supports more protocols (25+), can upload data, and is a library (libcurl). Wget specializes in recursive downloads and can mirror entire websites. Most developers use cURL for API work and Wget for bulk downloads.
Most browsers let you right-click a network request in DevTools and select "Copy as cURL". This generates a cURL command with all headers, cookies, and body data, making it easy to reproduce and debug requests outside the browser.
Adding -v to a cURL command shows the full HTTP handshake, including TLS negotiation, headers sent and received, and timing. This makes it invaluable for debugging SSL issues, redirect chains, and header-related problems.
The library behind cURL (libcurl) is used by PHP, Python (pycurl), Node.js, Ruby, and hundreds of other languages and tools. When your code makes HTTP requests, there is a good chance libcurl is doing the heavy lifting under the hood.