Mobile apps that transform your business

Four things move the cost: how many distinct screens and features it has, whether it needs its own server and database or connects to existing systems, whether it has to be built for both iOS and Android or just one, and how much payment or hardware integration it requires. We do not give a figure before understanding the scope, because a number pulled out on the first call is a guess. The initial survey and the written scope have no cost.

It depends on scope, but the important measure is not total duration: it is the rhythm of delivery. Every four to six weeks there should be something installable you can use. A project you only see at the end is a project where problems appear once there is no budget left to fix them. On top of that comes the app stores' review time, which is not in the developer's hands.

A hybrid app shares a single codebase for iOS and Android, comes out faster and cheaper, and today covers most business applications well. Native is justified when you need high graphics performance, heavy sensor use or very specific operating system features. For a catalogue, ordering, scheduling or customer service app, hybrid is usually the right call.

An app is justified when the user will come back many times, when it has to work offline, or when push notifications or access to the camera, GPS or sensors are needed. If what you want is for people to find you, learn about you and contact you, a well-built website does the job better and costs considerably less. We will say so even if it means a smaller project.

Developer accounts on each store, paid separately and in the company's name; a published privacy policy; a declaration of what data the app collects; and screenshots and icons at the sizes each store requires. Apple's review is stricter and can reject on design or content grounds, so it is worth allowing time for a second submission.

It should belong to your company, and it has to be in writing in the contract along with data ownership, the store accounts and how everything is handed over if the relationship ends. It is the first clause to review before signing, and the one that prevents the most problems later.