How does Dropbox work?

Question

How does Dropbox work? Is it just an FTP client with an easy-to-use web interface and support for many plarforms?

What makes it so useful to programmers, even for those who are working on web-based applications and who have FTP access to a server by default?

Does Dropbox come with an improved algorithm to facilitate file transfer for a better speed? What is the difference between an FTP client and Dropbox from a programmer's point of view?

Probably better posted on WebApps (http://webapps.stackexchange.com/) — Gavin, Aug 24 '10 at 08:32
Interesting article about the question http://blogs.ixiacom.com/ixia-blog/dropbox-looking-inside-the-protocol-behind-file-synchronization/ — Lukasz Frankowski, Apr 17 '15 at 06:19

score 17 · Accepted Answer · edited Sep 15 '13 at 02:43

FTP is just a way of copying files. And copying is not the same as synchronizing, which I believe is Dropbox's biggest strength.

Dropbox is a multiway synchronization system. This means if you are using your Dropbox account on many machines and editing different files on each machine, they will all be synchronised appropriately. With FTP you would have to delicately pick and choose which files need to be removed or added from each client to the server.

Another main difference is that synchronisation happens automatically whenever a file changes, which FTP does not do.

In terms of algorithms, I would guess that Dropbox uses file deltas for file transfer, which makes it much more efficient than FTP. This means only the parts of the file that changed are transferred instead of transferring the entire file every time it changes (see rsync).

I believe you are only asking about Dropbox's core functionality. Beyond that, Dropbox has lots of cool features that FTP does not like some revision control, photo gallery sharing, etc.

DropBox does use it's own protocol. But, in case you're curious, you can also try IQBox, which is an open-source sync client like DropBox that uses FTP as a backend. I'm the lead coder: https://code.google.com/p/iqbox-ftp/ — SilentSteel, Dec 09 '13 at 06:27
@Peter I completly agree dropbox should not be called as mere ftp client. Same thing can be achieved using FTP and other protocols as well. May I know the sources which you are denying they have used FTP? — dejjub-AIS, Aug 14 '15 at 17:43

score 4 · Answer 2 · edited Sep 15 '13 at 02:21

4

Dropbox files are not accessible by FTP. The API uses a REST-style architecture over the HTTP protocol. See Build the power of Dropbox into your app.

edited Sep 15 '13 at 02:21

Peter Mortensen

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answered Nov 19 '10 at 18:37

citrin

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http://mybackupbox.com allows you to transfer files between Dropbox and an FTP server. – Eric Warnke Mar 13 '12 at 16:06

How does Dropbox work?

2 Answers2

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