Users of curl

We estimate that there are more than twenty billion curl installations in theworld. It makes a good line to say but in reality we, of course, do not haveany numbers that exact. We just estimate and guess based on observations andtrends. It also depends on exactly what we consider "an installation". Let'selaborate.

Open Source

The project being Open Source and liberally licensed means that just aboutanyone can redistribute curl in source format or built into binary form.

Counting downloads

The curl command-line tool and the libcurl library are available for downloadfor most operating systems via the curl website, they are provided via thirdparty installers to a bunch and they come installed by default with even moreoperating systems. This makes counting downloads from the curl websitecompletely inappropriate as a means of measurement.

Finding users

So, we cannot count downloads and anyone may redistribute it and nobody isforced to tell us they use curl. How can we figure out the numbers? How can wefigure out the users? The answer is that we really cannot with any decentlevel of accuracy.

Instead we rely on witness reports, circumstantial evidence, on findings onthe Internet, the occasional "about box" or license agreement mentioning curlor that authors ask for help and tell us about their use.

The curl license says users need to repeat it somewhere, like in thedocumentation, but that is not easy for us to find in many cases and it is alsonot easy for us to do anything about should they decide not to follow thesmall license requirement.

Command-line tool users

The command-line tool curl is widely used by programmers around the world inshell and batch scripts, to debug servers and to test out things. There is nodoubt it is used by millions every day.

Embedded library

libcurl is what makes our project reach a really large volume of users. Theability to quickly and easily get client side file transfer abilities intoyour application is desirable for a lot of users, and then libcurl's greatportability also helps: you can write more or less the same application on awide variety of platforms and you can still keep using libcurl for transfers.

libcurl being written in C with no or just a few required dependencies alsohelp to get it used in embedded systems.

libcurl is popularly used in smartphone operating systems, in car infotainmentsetups, in television sets, in set-top boxes, in audio and video equipment suchas Blu-Ray players and higher-end receivers. It is often used in home routersand printers.

A fair number of best-selling games are also using libcurl, on Windows andgame consoles.

In website backends

The libcurl binding for PHP was one of, if not the, first bindings for libcurlto really catch on and get used widely. It quickly got adopted as a defaultway for PHP users to transfer data and as it has now been in that position forover a decade and PHP has turned out to be a fairly popular technology on theInternet (recent numbers indicated that something like a quarter of all sites onthe Internet uses PHP).

A few really high-demand sites are using PHP and are using libcurl in thebackend. Facebook and Yahoo are two such sites.

Famous users

Nothing forces users to tell us they use curl or libcurl in their services orin the products. We usually only find out they do by accident, by readingabout dialogues, documentation and license agreements. Of course somecompanies also just flat out tell us.

We used to collect names of companies and products on our website of usersthat use the project's products "in commercial environments". We did thismostly just to show-off to other big brands that if these other guys can buildproducts that depend on us, maybe you can, too?

The list of companies contains hundreds of names, but extracting some of thelarger or more well-known brands, here's a pretty good list that, of course,is only a small selection:

Adobe, Altera, AOL, Apple, AT&T, BBC, Blackberry, BMW, Bosch, Broadcom,Chevrolet, Cisco, Comcast, Facebook, Google, Hitachi, Honeywell, HP, Huawei,HTC, IBM, Intel, LG, Mazda, Mercedes-Benz, Microsoft, Motorola, NASA, Netflix,Nintendo, Oracle, Panasonic, Philips, Pioneer, RBS, Samsung, SanDisk, SAP, SASInstitute, SEB, Sharp, Siemens, Sony, Spotify, Sun, Swisscom, Tomtom, Toshiba,VMware, Xilinx, Yahoo, Yamaha

Famous high volume apps using curl

The Google Youtube app, the Google Photos app, Spotify, Instagram, Skype (onAndroid), bundled with iOS, Grand Theft Auto V, Fortnite.