Phase-by-phase breakdown
Every app development project has four phases. The timelines below are for a focused, well-scoped project with a senior team:
- Discovery (1–3 weeks): Scope definition, data model, integration mapping, acceptance criteria, fixed-price proposal. This phase prevents the scope changes that cause delays in every other phase.
- Design (1–4 weeks): Wireframes, component library, high-fidelity screens. Depends on the number of distinct screen types. A focused MVP has 8–15 screens; a full platform has 30–60.
- Build (6–16 weeks): The longest phase. Frontend, backend, integrations, QA. Weekly staging demos. The timeline compresses significantly with AI-assisted tooling in the hands of experienced engineers.
- Launch (1–2 weeks): Deployment, App Store / Google Play submission, review period, go-live. App Store review adds 1–3 days (iOS) or 1–7 days (Android).
Timeline by product type
- Focused web MVP: 8–10 weeks
- Native iOS or Android MVP: 10–14 weeks
- Cross-platform mobile (React Native): 12–16 weeks
- SaaS product (auth, billing, admin): 12–18 weeks
- Full v1 platform: 16–24 weeks
- Enterprise / regulated industry: 20–32 weeks
- Healthcare with EHR integration: 24–36 weeks
Add 2–4 weeks for any project that requires a third-party legacy API integration (ERP, POS, EHR) where the API documentation is incomplete or the vendor's sandbox is unreliable.
What causes delays
In order of frequency:
- Scope changes after discovery: The most common and most avoidable delay. A formal change order process — scope is defined before build, changes require a written order — eliminates this almost entirely.
- Slow client feedback: A two-week design review that could have been three days. Batch feedback, designate a decision-maker, set a feedback deadline on every review.
- Third-party API issues: The vendor's sandbox is broken, the documentation is wrong, or the API behaves differently in production. We buffer for this in estimates.
- App Store rejection: Avoidable with a pre-submission review against current guidelines. We do this as standard. When it happens anyway, add 1–2 weeks.
- Unclear acceptance criteria: "The design should look good" is not an acceptance criterion. Specific, testable criteria agreed in discovery eliminate subjective disputes at sign-off.
How AI tooling changes timelines in 2026
AI-assisted development has meaningfully compressed build timelines for experienced engineers who use it well. Our current estimate: 20–35% compression on the build phase for standard CRUD features, less for novel or highly integrated functionality.
What AI tooling doesn't accelerate: discovery (a human process), design (a human process), App Store review (Apple's process), and third-party API integration (where the bottleneck is the vendor's documentation, not the code).
The compressor effect compounds with experience. Engineers who have been using AI tooling for 18+ months are consistently faster than those who adopted it recently. The quality of the prompt matters as much as the quality of the code review.
App Store and Google Play review timelines
App Store review (iOS) currently runs 1–3 days for first submissions and 1–24 hours for updates. Rejection adds 1–3 weeks for fixing the issue and resubmitting.
Google Play review runs 1–7 days for new apps, 1–3 days for updates. Google uses automated review for most updates; new apps get more scrutiny.
Common rejection reasons: privacy manifest issues (iOS), data safety form inaccuracies (Android), in-app purchase policy violations, and content policy flags. We review against current guidelines before every submission.