- Screen count is a weak predictor of cost — backend complexity and integrations drive it more.
- An app with no backend of its own is the cheapest, fastest category by far.
- Payments, real-time features, and offline sync each add meaningfully to scope.
- Store submission and post-launch support should be budgeted as separate line items.
Screen count is the wrong metric
Two apps with the same number of screens can have wildly different costs depending on what's happening behind those screens — a simple content app with static data is a different project entirely from an app doing real-time sync, payments, and complex backend logic with the same visual screen count.
No custom backend is the cheapest tier
Apps that are essentially a front-end onto an existing backend or a simple content management system, with minimal custom server-side logic, are the fastest and least expensive category — often a matter of weeks rather than months.
Payments and real-time features add real scope
Integrating payments properly (with all the edge cases — refunds, failed charges, subscription management) and building real-time features (live chat, live tracking) both add meaningful backend complexity and testing surface, and should be budgeted as distinct additions, not assumed to be included in a base estimate.
Offline support is often underestimated
Making an app work reliably offline — caching data locally, syncing changes when connectivity returns, handling conflicts — is one of the most commonly underestimated pieces of mobile app scope, because it touches nearly every screen rather than being one isolated feature.
Budget store submission and support separately
App Store and Play Store review, plus the post-launch period of crash fixes and OS-update compatibility, are real work that's easy to leave out of an initial estimate. Treating them as their own line items, rather than assuming they're absorbed into 'development,' produces a more accurate total.