Kivy – Open-source Python library for rapid development of applications

> Kivy (as a group) must have spent money in marketing the product

I don't think kivy (as a group) does anything except recently the contest, and things like maintaining a g+ account, mailing list, posting on hn or reddit if something intersting happens etc. - were you thinking of anything in particular here?

> launching developer contests

This was funded entirely from sponsorship, you can see the list on the contest page (http://kivy.org/#contest).

> publishing books on Kivy (I've seen a couple books on Kivy by O'reilly)

Publishers commission books because they think they will make money, not because kivy pays them to - actually, I don't think any of the core developer team have been directly involved in kivy books.

> and other stuff

Honestly, not really - I can't think of any other expenses except small things like powering the website server.

> I've always been confused about open-source projects that go big on marketing themselves.

I don't think kivy is really big on marketing itself - if anything, maybe the opposite. I've wondered before if its relatively unknown status (compared to phonegap etc) is at least partly because we don't advertise much, though it may just as well be that more people are interested in html.

Things like the developer contest are great to build interest and get the word out that kivy exists, and as you said yourself have obvious advantages in maintaining and growing the community - if this is 'going big' on marketing, I don't think that term is very meaningful.

I have a couple hymnal apps in the Play Store built with Kivy, and reviews suggest that performance is a problem for some people, especially scrolling through long views. I'm in the process of rewriting them using HTML and JavaScript in a WebView.

That being said, Kivy is really nice to work with; the documentation is good and it's a well thought-out library. I'd enjoy using it for future apps that don't happen to have long views to scroll through.

There's a (probably not exhaustive) list at https://github.com/kivy/kivy/wiki/List-of-Kivy-Projects#kivy... .

QT has tried that on Android and it's an exceedingly poor solution. Almost no user will click to download additional files -- they've been (rightfully) conditioned to view this as a suspicious technique.

As long as you blacklist unneeded libraries on Kivy, you can get the size down to 5 - 10 MB. I personally don't believe this download size is such a problem for users (many native Java apps are upwards of 5 MB).

What is a problem is the start-up time and battery usage, both much harder problems to address. Because they require the Python interpreter, Kivy apps take significantly longer to start-up, and use significantly more battery power than Java apps. I have some hope that Micropython may eventually offer a solution to this for Python on Android, although porting Kivy to Micropython will be a major task.

I confirm there was no money directly spent on promoting kivy. Most of our communication has been directly with the community, through help on irc/google-groups/SO and other places. We did start to improve communication on twitter/g+/facebook, but it's really on our own time, not paying any agency or specialist of these things.

For books, while we were contacted by a few publishers, none of the core-dev authored any, yet. We tried to give a hand, however, reviewing the books when we could, i personnaly reviewed O'Reilly's book, pointing out a few mistakes to the editor, and gave it a good review, as it was, in my opinion, a well written book with very good exemples and explanations. As it seems usual, i got a free book and a little payment for this (that i didn't expect at all when doing it, my motivation was that there was a need for good kivy books).

And i agree we should do more, if not on marketing, at least on communication (there are a few markets that kivy can fully or partially cover already, we don't want to limit these options, just help it grow where users want to use it), but users need to know about it, and to easily get a good understanding of what's possible to do with it. We have a lot of recurring questions about that, as well as people discovering us and asking why they didn't heard about us sooner.

I do think the community could be way bigger, but we need to adapt the tools we use to communicate, irc works very well up to the hundred of connected users we have, probably less at more, and waste a lot of energy in saying the same things over and over again (although the direct interaction with our users is highly appreciable), SO seems to make reuse of explanations much more common, and is sometime more effective than direct documentation.

Anyway, i'm getting away from the point, will cut it there. :)