cURL is the name of the project. The name is a play on 'Client for URLs',
originally with URL spelled in uppercase to make it obvious it deals with
URLs. The fact it can also be pronounced 'see URL' also helped, it works as
an abbreviation for "Client URL Request Library" or why not the recursive
version: "Curl URL Request Library".
The cURL project produces two products:
A free and easy-to-use client-side URL transfer library, supporting FTP,
FTPS, HTTP, HTTPS, GOPHER, TELNET, DICT, FILE and LDAP. libcurl supports
HTTPS certificates, HTTP POST, HTTP PUT, FTP uploading, kerberos, HTTP
form based upload, proxies, cookies, user+password authentication, file
transfer resume, http proxy tunneling and more!
libcurl is highly portable, it builds and works identically on numerous
platforms, including Solaris, NetBSD, FreeBSD, OpenBSD, Darwin, HPUX,
IRIX, AIX, Tru64, Linux, UnixWare, HURD, Windows, Amiga, OS/2, BeOs, Mac
OS X, Ultrix, QNX, OpenVMS, RISC OS, Novell NetWare, DOS and more...
libcurl is free, thread-safe, IPv6 compatible, feature rich, well
supported and fast.
A command line tool for getting or sending files using URL syntax.
Since curl uses libcurl, it supports a range of common Internet protocols,
currently including HTTP, HTTPS, FTP, FTPS, GOPHER, LDAP, DICT, TELNET and
We pronounce curl and cURL with an initial k sound: [kurl].
There are numerous sub-projects and related projects that also use the word
curl in the project names in various combinations, but you should take
notice that this FAQ is directed at the command-line tool named curl (and
libcurl the library), and may therefore not be valid for other curl-related
projects. (There is however a small section for the PHP/CURL in this FAQ.)
1.2 What is libcurl?
libcurl is a reliable and portable library which provides you with an easy
interface to a range of common Internet protocols.
You can use libcurl for free in your application, be it open source,
commercial or closed-source.
libcurl is most probably the most portable, most powerful and most often
used C-based multi-platform file transfer library on this planet - be it
open source or commercial.
7.1 What is PHP/CURL?
The module for PHP that makes it possible for PHP programs to access curl-
functions from within PHP.
In the cURL project we call this module PHP/CURL to differentiate it from
curl the command line tool and libcurl the library. The PHP team however
does not refer to it like this (for unknown reasons). They call it plain
CURL (often using all caps) which causes much confusion to users which in
turn gives us a higher question load.
7.2 Who write PHP/CURL?
PHP/CURL is a module that comes with the regular PHP package. It depends and
uses libcurl, so you need to have libcurl installed properly first before
PHP/CURL can be used. PHP/CURL is written by Sterling Hughes.