Is it possible to install third-party apps on an iPhone? If not, how is it controlled?

Question

Can I go around Apple and offer applications to users, or do they force you to go through them? How? Just legally?

Answer 1

Aside from the App Store (and jailbreaking), Apple provides two official routes to install applications on the iPhone.

1. Enterprise Distribution: designed for internal users of a company
2. Ad Hoc Distribution: allows your app to be installed on up to 100 iPhones

Source: http://developer.apple.com/iphone/program/distribute.html

Answer 2

If you wish to distribute applications to phones with out going through the App Store, you must sign each copy of your application for a specific phone handset. If you need more wide spread distribution, all your client phones must be "jail broken". Once a phone is jail broken, it will accept any application for installation.

Answer 3

You can offer applications through Cydia for jailbroken iPhones / iPods. Cydia uses a system similar to Debian's apt. Basically allows users to add custom "sources" (repositories) and install applications provided by those sources.

Obviously this is not supported or approved by Apple since it circumvents the App store and their App approval process.

Answer 4

For phones that are not jailbroken, distribution rules are enforced by the iPhone's code-signing system. The phone won't run any apps that aren't signed by Apple, and the only way to get an app signed is either to get it into the app store or to use ad-hoc distribution.

Ad-hoc is effective but time consuming for more than a few devices, in that you have to get the unique device ID for each device you want to distribute the app to. You then sign the app for that device and send a copy along with a provision file. Some batching is possible-- you can get up to 100 devices in the same ad-hoc build. But if/when Apple finds out you're doing it, they'll close your iPhone developer account (for violating the rules) and then you won't be able to generate any more provision files.

One developer tried using the ad-hoc approach last year when Apple rejected their app (Podcaster). They claimed to have sold something like 1100-1200 copies before Apple shut them down.

Jailbroken phones don't have this limitation, but it's up to you to determine (a) whether the market is big enough and (b) whether enough of those people will be willing to pay for your app. I don't know the answers-- it could well be "yes" to both-- but don't just assume they're true without investigating enough to make a reasonable prediction.