My partner and I are developing an app for someone else. They will pay us lump sums for the phases of the development, but we also want "royalties" for the income generated by the app in the future.<p>We couldn't do the project without info and access provided by them, and they couldn't do it without our technical skills. Any idea of what would be a reasonable/normal percent?<p>Can't find much talk of it online, since most people seem to develop apps for themselves. Any tips would be welcome. Thanks.