"How long will it take" usually arrives together with "and how much will it cost", and both answers depend on the same thing: what exactly you are building. So instead of one number, here is a breakdown of the time by stage and by app type, followed by the list of what actually delays projects.
Timeline by stage
| Stage | Typical time | What happens |
|---|---|---|
| Problem and users | A week | What the app solves, for whom, and what is out of version one |
| Scope and UX | 2–3 weeks | Flows, 5–10 screens, a clickable prototype tested with users |
| Architecture and backend | 3–6 weeks (in parallel with the app) | Data model, API, authentication, permissions, notifications, monitoring |
| App development | 4–8 weeks for an MVP | One- to two-week iterations, an installable build in each |
| QA on real devices | 2–3 weeks | Screens, OS versions, slow networks, offline, denied permissions |
| Store review | One to two weeks | Accounts, privacy policy, screenshots, a review round and rejections |
The stages overlap: the backend is built in parallel with the first screens, and QA runs in every iteration rather than only at the end. That is why a focused MVP ships in 8–12 weeks even though the stages add up to more.
How long by app type
Focused MVP: 8–12 weeks
Sign-up and login, 5–10 core screens, a basic backend, push notifications, analytics. This is the version that proves the idea works with real users. The condition: a first version that is actually small, and a client who makes decisions in days, not weeks.
Mid-size app: 4–6 months
Everything in the MVP, plus payments, an admin panel, a few integrations (CRM, payments, delivery), roles and permissions, and reports. Most business apps live here. The time is set mainly by the number of integrations and the depth of the admin panel.
Product with realtime or AI: 6–12 months
Realtime location, chat, dispatch, AI engines that have to be reliable rather than just impressive in a demo. Here most of the time goes into the backend, load testing and AI evaluation, not the screens.
What actually delays app projects?
- A scope that changes mid-way. Every feature added after the architecture is set costs several times the same feature in the scope. This is the number one delay, by far.
- Decisions that wait. A weekly demo with no response, a design waiting for approval, access to a third-party system not granted. Days of waiting add up to weeks.
- Integrations that depend on others: a payment provider's API, an old ERP, an account that needs opening. These are outside the dev team's control and so must start first.
- App Store review. A rejection over a policy clause, a login screen or content can add one to two weeks per round. Prepare it in advance, do not discover it on launch day.
- QA postponed to the end. Bugs found after three months of development are expensive and slow to fix; bugs found in every iteration are fixed within hours.
How to shorten development time without paying for it later
- A genuinely small first version: the one thing the app does, plus a few necessary layers. Everything else goes on the list for version two.
- React Native with Expo instead of two native teams: one codebase for iOS and Android, and OTA updates that bypass the review round for small fixes.
- One decision-maker on the client side, with a one- to two-day turnaround on demos and questions.
- Start the integrations and store accounts in the first week, not the last month.
- Do not cut QA, automated tests or DevOps. They are what lets you release fast without breaking things.