cURL basics
What does cURL mean?
cURL stands for Client URL. In everyday developer usage, it refers to the curl command-line tool used to transfer data to or from a URL.
The short answer
cURL originally means Client URL. The project name is usually written as cURL, while the command you type in a terminal is lowercase: curl.
Developers use curl to make HTTP requests, test APIs, download files, follow redirects, send headers, post JSON, and reproduce browser network requests from the command line.
A basic curl example
A curl command starts with curl, followed by a URL and optional flags. The flags describe the request method, headers, body, authentication, timeout, and other behavior.
curl https://api.github.com/repos/curl/curlWhy cURL matters for APIs
API documentation often uses curl because it is compact, cross-platform, and precise. A curl command can show the exact URL, HTTP method, headers, and request body needed to call an endpoint.
That also makes curl a useful bridge between documentation and application code. Once you understand the request, you can convert the curl command into Python, JavaScript, Node.js, Go, PHP, Java, Ruby, or another language.
cURL versus libcurl
The curl command is the tool most developers type in a terminal. libcurl is the underlying transfer library that software can use directly. They are related, but they are not the same thing.
For most API work, you only need the curl command. If you are building lower-level networking software, libcurl may matter more.
Try it with curlcode
Have a curl command already? Paste it into one of the converters below to generate language-specific HTTP request code.
Frequently asked questions
Is cURL a programming language?
No. cURL is a command-line tool and library for transferring data. It can help you test requests before writing code in a programming language.
Should I write cURL or curl?
Use cURL when referring to the project name and curl when referring to the terminal command.
Why do API docs show curl examples?
curl examples are concise and easy to run from a terminal, so they are a convenient way to document an HTTP request.
Can I turn a curl command into code?
Yes. You can convert curl commands into language-specific HTTP request code, such as Python requests, JavaScript fetch, or Node Axios.
Related guides
What is a cURL command?
A practical explanation of curl commands, their structure, common flags, and how developers use them to test APIs.
How to copy as cURL from Chrome DevTools
Use Chrome DevTools to copy a real browser request as cURL, inspect headers and cookies, and convert it into reusable code.
How to send a POST request with JSON using cURL
Learn how to send JSON with curl using POST, Content-Type headers, and request bodies that APIs can parse correctly.