curl

» go to curl.se now (it still works)

~ what it is ~

somewhere in your house, something is running curl. it is a command line tool and a library, libcurl, for moving data to and from urls. http, https, ftp, sftp, smtp, imap, mqtt, a few dozen protocols in total, on 29 platforms, with bindings for more than 50 programming languages. you type curl and a url and the bytes arrive. that is the entire pitch and it has been enough for almost thirty years.

the project began in 1996 as httpget, a small tool daniel stenberg adopted to fetch currency exchange rates for an irc bot. it became urlget, then curl, with the first release under that name on march 20, 1998. the scope grew one protocol at a time. the maintainer never changed.

~ where it ended up ~

the project keeps a public list of places curl is known to run, and the list reads like an inventory of the physical world. cars from more than twenty manufacturers, toyota, tesla, bmw, mercedes, ford. televisions from samsung, lg, sony, philips. printers, set-top boxes, audio receivers, games from nintendo and rockstar and ea. apple ships it, google ships it, microsoft put it directly into windows 10, which means the most microsoft operating system there is now includes a swedish hobby project from 1998 as a built-in command.

the count the project uses is over twenty billion installations. nobody can verify a number like that precisely and nobody seriously disputes it either. if a device has a network stack and a browser is too heavy for it, the safe bet is that libcurl is in there doing the fetching.

~ the guy ~

daniel stenberg has led curl since before it was called curl. he works on it full time now, funded through support contracts and sponsors, and he writes about the project with a transparency that most companies would classify as a security incident. because the curl license text ships in car infotainment menus, he periodically gets emails from confused car owners asking him to fix their gps, their dashboard, or in one case their vehicle. he is one person. the emails assume he is a department.

this is the part worth sitting with. a nontrivial slice of the world's data transfer depends on a project whose bus factor conversations involve an actual, specific man in sweden. it works because he has been consistent for decades, because the code is open, and because hundreds of contributors orbit the project. but the center of it is still him, answering issues, cutting releases on a fixed cadence, version 8.21.0 as of mid 2026.

~ what it outlived ~

the download manager was a whole software category once. getright, gozilla, a shelf of shareware that promised to resume your interrupted downloads, with toolbars and ads and registration nags attached. all of it is in the ground. curl did the same job with no interface at all, cost nothing, nagged nobody, and got absorbed into everything instead of dying as a product. not having a business model turned out to be the winning business model.

~ why it still matters ~

curl is what infrastructure looks like when it goes right. free, boring, documented, maintained, everywhere. no rebrand has ever happened to it. no growth team has ever touched it. it moves bytes from one place to another, it has done so since the dial-up era, and it will very likely outlast most of the devices it is currently installed in.

i type curl most working days and have for twenty years. it is one of an extremely short list of tools i learned in the nineties that behaves today exactly the way it behaved then, except better.

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