Mobile App Development — iOS & Android Agency

Q: How much does it cost to build a mobile app?

An MVP starts at €15,000 , a full iOS + Android application with a back office typically runs between €35,000 and €80,000 , and a business platform or marketplace usually exceeds €100,000. Three things move the price: screen count, third-party integrations (payments, ERP, CRM) and whether you target one platform or two.

Q: How long does mobile app development take?

Roughly 4 to 8 weeks for an MVP , 3 to 4 months for a полished application and 5 to 8 months for a complex platform. Add Apple and Google review: 24 to 72 hours for the App Store, a few hours to a few days for Google Play.

Q: Native or cross-platform — which should we choose?

Cross-platform (React Native, Flutter) fits the large majority of projects: one codebase for both stores, roughly 30–40 % less budget and twice the iteration speed. Native (Swift, Kotlin) remains preferable when the app leans heavily on hardware: augmented reality, real-time video processing, low-level Bluetooth, advanced system widgets.

In short

Custom mobile app development costs between €15,000 and €120,000 and takes from 4 weeks (MVP) to 6 months (full platform). Price depends on feature count, integrations with your existing systems, and whether you go native (Swift, Kotlin) or cross-platform (React Native, Flutter).

55 · agency covers the whole cycle — discovery, design, engineering, store submission and ongoing maintenance — from Paris, Nice and Lyon. Free quote within 24 hours.

What we build

Six areas,
one standard.

Consumer apps (B2C)

Content, loyalty, community and social products. Built for retention: careful onboarding, smart notifications, perceived performance.

Business apps (B2B)

Field tools, job management, offline capture and deferred sync, connected to your ERP or CRM. Built to save your teams time.

E-commerce & marketplaces

Catalogue, cart, Stripe or Adyen payments, multi-vendor management and order tracking.

Connected & IoT apps

Bluetooth Low Energy, sensors, wearables, Apple Watch and Wear OS — a field where native still has the edge.

AI-powered apps

Embedded assistants, semantic search, image recognition and content generation. See our AI expertise.

Legacy app rebuilds

Technical audit, progressive migration and a design and performance refresh without losing your existing user base.

How we work

Every stage ships
something you can judge.

A method proven on more than 150 projects. Each stage produces a concrete deliverable, validated before moving on — no tunnel effect.

Product discovery

1–2 weeksDiscovery workshop, personas, MoSCoW prioritisation, technical decisions and a costed estimate. You leave with a clear scope and a firm budget.

Design & prototype

2–4 weeksWireframes, art direction, Figma design system and a clickable prototype tested with real users — before a single line of code.

Engineering

6–20 weeksTwo-week sprints, a demo at the end of each one, installable builds on your own phones through TestFlight and Google Play Console.

QA & release

2–3 weeksFunctional testing on a real device fleet, bug fixing, store listings and ASO, then submission to Apple and Google through to approval.

Run & evolve

ongoingCrash and performance monitoring, usage analysis, iOS/Android compatibility updates and the next versions, driven by your priorities.

What you get

A complete engagement, no lock-in.

Full source code transferred to your Git repository, documented.
Figma design system delivered and reusable by your own teams.
Admin back office and documented API (OpenAPI).
App Store and Google Play release, ASO listings included.
GDPR compliance: records, privacy policy, consent management.

SwiftSwiftUIKotlinJetpack ComposeReact NativeFlutterExpoNode.jsFirebaseGraphQLStripeAWS

150+projects delivered since 2013

40people across product, design and engineering

100 %of the code transferred to you

Budget & timeline

What it costs,
honestly.

Real ranges from delivered projects. The firm quote follows the framing workshop.

Indicative budgets and timelines for mobile app development
Project type	Budget	Timeline	Scope
Mobile MVP	€15,000 – 30,000	4–8 weeks	One platform, 6 to 10 screens, light back end. To validate the market.
Full application	€35,000 – 80,000	3–4 months	iOS + Android, 20 to 35 screens, back office, payments, notifications.
Business platform / marketplace	€90,000 – 250,000	5–8 months	Multi-role, system integrations, real time, security and compliance requirements.
Legacy app rebuild	€25,000 – 70,000	2–5 months	Audit, progressive migration, no disruption for existing users.
Maintenance	€900 – 3,500 / month	ongoing	OS compatibility, fixes, monitoring, small improvements.

FAQ

Frequently asked questions

How much does it cost to build a mobile app?

An MVP starts at €15,000, a full iOS + Android application with a back office typically runs between €35,000 and €80,000, and a business platform or marketplace usually exceeds €100,000.

Three things move the price: screen count, third-party integrations (payments, ERP, CRM) and whether you target one platform or two.

How long does mobile app development take?

Roughly 4 to 8 weeks for an MVP, 3 to 4 months for a полished application and 5 to 8 months for a complex platform. Add Apple and Google review: 24 to 72 hours for the App Store, a few hours to a few days for Google Play.

Native or cross-platform — which should we choose?

Cross-platform (React Native, Flutter) fits the large majority of projects: one codebase for both stores, roughly 30–40 % less budget and twice the iteration speed.

Native (Swift, Kotlin) remains preferable when the app leans heavily on hardware: augmented reality, real-time video processing, low-level Bluetooth, advanced system widgets.

Who owns the code and the store accounts?

You do, entirely. Rights are contractually transferred in full. Code ships to your own Git repository, documented, with build and deployment scripts. Apple Developer and Google Play accounts are opened in your name — you keep your listings, users and revenue even if you change providers.

Do you publish the app to the App Store and Google Play?

Yes, release is part of the engagement. We prepare store listings (title, ASO-optimised descriptions, screenshots, preview video), handle compliance (privacy policy, data-collection declaration, age rating) and manage the review process through to live.

Do you work with startups as well as large companies?

Both. We have taken startups from idea to funding round, and worked with the digital teams of groups such as Decathlon. The working mode adapts: short pragmatic cycles for startups; compliance, security and system integration for enterprises.

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Mobile app development for iOS & Android.