App Development: The Process from Idea to App Store

App development runs in five phases: consulting and concept, UI/UX design with a clickable prototype, development and testing, publication in the stores, and support with further development. If you clarify the target group, the scope of the first version and operation early, you avoid the most expensive mistakes – and launch with an app that people actually use.

This article walks through the process phase by phase: what happens, which decisions are due and where projects typically stall – this is how we work at Nano Concepts, from the first sketch to publication on the App Store and Google Play.

The process at a glance

Phase	Deliverable	Your contribution
1. Consulting & concept	Concept for the first version (MVP), rough schedule, basis for the quote	Goals, target group, priorities, existing systems
2. UI/UX design & prototype	Screens and clickable prototype, insights from user tests	Feedback, test participants from the target group
3. Development & testing	Working interim versions, backend, admin area, tested app	Sign-off of each stage, testing on your own smartphone
4. Publication	Store listings, approval by Apple and Google	Developer accounts, legal texts, privacy disclosures
5. Support & further development	Updates, new features, usage analysis	Feedback, budget for operation and maintenance

Phase 1: Consulting & concept

Who will use the app, which problem does it solve, and which features does the first version need? The answers become a lean concept for an MVP – the smallest version that delivers real value. Everything else follows later, based on real user feedback.

In this phase we also settle the fundamental questions that save a lot of money later:

• Target group and usage situation: on the move, in the office, or wearing gloves on a construction site?
• Platforms: iOS, Android, web – or all of them?
• Business model: free, subscription, in-app purchases or an internal tool
• Data handling: Which data is created, where is it stored, and what applies for data protection?

How to define the scope of the first version

Sort all wish-list features into three groups: must-have (without them the app has no value), should-have (makes the app clearly better) and nice-to-have (pleasant, but dispensable). The first version contains the must-haves and at most the most important should-haves. For an app for service technicians, a job list, status updates and photo documentation belong in the first group, while a chat or reporting dashboards belong more in the third.

At the end of this phase there is a document that records the goal, the features of the first version and the rough schedule – the basis for a transparent quote. How the costs break down is explained in the article How much does an app cost?

Native app, cross-platform or PWA?

One of the most important decisions is made in the concept phase: the technology. Native apps, cross-platform apps and progressive web apps differ mainly in effort, device access and distribution.

Criterion	Native app	Cross-platform app	Progressive web app
Codebase	separate per platform	one shared codebase, e.g. with React Native or Flutter	one, runs in the browser
Device features	full access	largely, partly via additional modules	limited depending on browser and device
Distribution	App Store and Google Play	App Store and Google Play	by link, without a store
Effort for development and maintenance	highest	medium	often the lowest

Which option fits depends on features, target group and budget. For many business apps, cross-platform is a good compromise; if you make intensive use of the camera, sensors or background processes, native development is often the better choice. When a PWA pays off and where its limits lie is explained in the article Progressive web apps: offline capability and business case.

Phase 2: UI/UX design & prototype

Together with our partner agency LOMA DESIGN, we create screens and a clickable prototype. You test the app before a single line of code is written – this is when changes are cheapest.

Good app design follows the conventions of each platform: users expect different gestures and patterns on an iPhone than on Android, and both vendors set the framework with their design guidelines (Apple’s Human Interface Guidelines, Google’s Material Design). We test the prototype with people from the target group. Even a few short tests often show where someone gets stuck.

Pay attention to things that are unremarkable in the office but decisive in the field: large buttons, readable contrasts, operation with one hand or with gloves. If consumers can conclude contracts in the app, accessibility is part of the design from the start as well. More on our approach: UI/UX design.

Phase 3: Development & testing

We develop in stages with regular interim versions. We build the backend, interfaces and database from the outset so that the app can grow. Almost every app consists of more than what users see on the screen: a backend with an API, an admin area for managing content and users, push notifications and often connections to existing systems.

What should be tested

Testing is done on real devices of different sizes and operating system versions – a simulator is no substitute. Through TestFlight at Apple and internal testing at Google Play, you try out interim versions yourself on your smartphone. Besides the normal case, we check the situations in which apps fail in everyday use:

• weak or interrupted connections, including switching between Wi-Fi and mobile data
• denied permissions, for example for camera, location or notifications
• interruptions from calls, messages or switching to another app
• large text, dark mode, small and large displays

After launch, crash reporting shows where and on which devices the app crashes.

Phase 4: Publishing on the App Store and Google Play

Store listings, screenshots, descriptions and the review by Apple and Google: we handle the publishing and make sure all requirements are met. To keep publication from becoming a bottleneck, you should get these items started early:

• Developer accounts in your company’s name: This way the app stays yours permanently. For company accounts Apple requires, among other things, a D-U-N-S number, and Google usually requires one for organization accounts as well – apply for it in good time. Apple charges an annual fee, Google a one-time registration fee.
• Data protection: Both stores require a privacy policy and information on which data the app collects. If the app offers a user account, the account must be deletable within the app.
• Access for reviewers: If the app has a login, the reviewers need test credentials with sample data.

The review can lead to follow-up questions. With carefully prepared documents it goes much more smoothly, but you should still build a buffer into the schedule. Common stumbling blocks are missing privacy disclosures, test logins that do not work, and apps that are little more than an embedded website – Apple often objects to such apps for lack of minimum functionality.

Internal apps without a public store listing

Not every app needs to be visible to everyone. Pure employee apps can be rolled out through Apple’s custom app distribution in Apple Business Manager and through private apps in Managed Google Play, usually together with device management (MDM). As a rule, the app still goes through the platform operators’ review.

Law and data protection from the start

Apps almost always process personal data – from the login to location sharing. Clarify early which data is really needed, how consent is obtained and which third-party services are used; this makes the privacy policy and the store disclosures easier. If consumers can conclude contracts in the app, Germany’s Accessibility Strengthening Act (BFSG), which has applied since June 28, 2025, may also apply – accessibility is easier to build into the design than to retrofit in the code.

Phase 5: Support & further development

After launch, the real work begins: updates, new features and analysis of usage. Apple and Google release new operating system versions every year, adjust their policies and regularly require apps to be built with current development tools and target versions. An app that is not maintained will eventually stop working properly or disappear from the stores. So plan for maintenance and further development from the start.

An app in the store is not yet an app that gets used. It takes meaningful screenshots and descriptions, onboarding that shows the benefit within the first seconds, and push notifications that inform rather than annoy. For business apps, internal rollout is added: anyone who is supposed to use the app needs to know why – and how.

Measure from the start, in compliance with data protection rules, which features are used and where users drop off – this is the best basis for prioritizing the next features.

Duration, practical example and common mistakes

How long does app development take?

The honest answer: it depends on the scope. A lean first version with a clearly limited range of features can be built in a few weeks to a few months; we plan complex apps with many roles, interfaces and offline features in milestones. The schedule is influenced most by the clarity of the requirements, the speed of your decisions, the number of interfaces and the lead time for developer accounts and store review. In the initial consultation, you receive a realistic estimate.

Practical example: field technician app for a service company

Suppose a service company wants to capture the jobs, checklists and photos of its technicians digitally – so far everything runs on paper slips and phone calls. The process could look like this:

1. Concept: job list, status updates, photos and customer signature. Because many jobs take place in basements, it is settled early that the app must work offline – which significantly affects architecture and effort.
2. Platform: The company provides uniform company smartphones – which favors a single platform or cross-platform and internal distribution instead of a public store listing.
3. Prototype: Two or three technicians test it. Result: larger buttons for operation with gloves and fewer steps for the status update.
4. Development and operation: in stages with interim versions on the company devices, plus a backend and admin area for dispatching; after launch, training, an error-reporting channel and updates with their own budget.

Why app projects fail

• too many features in the first version – the project gets expensive before it has users
• no clear goal and no clear target group – the app tries to please everyone
• no planning for operation and updates – after launch there is no budget for maintenance
• no testing with real users – assumptions replace insights
• store requirements underestimated – the launch is delayed

Checklist for your initial consultation

The more you bring to the first meeting, the more concrete the assessment will be. Helpful items are:

• a short description of the idea and the problem the app solves
• the target group and typical usage situations
• a list of the most important features, sorted by priority
• existing systems the app should exchange data with
• your desired time frame and a rough budget range

How Nano Concepts supports you

We support you from the first sketch to the store – and beyond: from consulting and concept through UI/UX design and prototype, which we create together with our partner agency LOMA DESIGN, to development, publishing and support. The developer accounts are registered to your company. You can find all the details of our services on the Mobile Apps page. In the free initial consultation, you receive a realistic assessment of scope and time frame.

This article does not replace legal advice.