Development
Mobile app development for iOS and Android
A mobile app is software installed on your users' phones or tablets and distributed through the App Store and Google Play. It gives access to device features: push notifications, camera, geolocation, payment, biometrics and offline use.
Agencei builds mobile apps for companies that need a direct channel with their customers, members or field teams: service apps, business apps for technicians, companion apps for a connected product or an existing SaaS.
Depending on your context, we choose between native (Swift, Kotlin) and cross-platform development with React Native and Expo, which delivers iOS and Android from a single codebase. We handle the full cycle: scoping, screen design, development, backend, app store publication and maintenance.
When do we step in?
Launching a new mobile service
You have a product idea or a service to offer on mobile and need a reliable first version, published on both stores, to test the concept with real users.
Equipping field teams
Technicians, delivery drivers, sales reps or auditors work away from the office, sometimes without network coverage. A business app with offline mode and synchronization replaces paper forms and double entry.
Extending an existing web product
Your web platform works, but your users are asking for an app: notifications, quick access, camera. We design the mobile app on top of your existing APIs.
Replacing an ageing app
Your current app is hard to maintain, rejected by the stores or incompatible with new iOS and Android releases. We rebuild it on a modern foundation without losing your users.
Building the companion app for a connected device
Your product communicates over Bluetooth or Wi-Fi and needs an app for pairing, configuration and data monitoring.
How we work
- 1
Scoping and prioritization
We clarify use cases, target users and technical constraints (offline, security, devices). The scope of the first release is reduced to what delivers value immediately.
- 2
Screen design and prototype
User journeys are mocked up and tested as a clickable prototype before any development, to validate usability and avoid expensive rework.
- 3
Iterative development
The app is built in functional batches, with test builds distributed regularly through TestFlight and Google Play to collect your feedback.
- 4
Backend and integrations
We build or adapt the API, authentication, push notifications and connections to your tools (CRM, ERP, payment).
- 5
Real-device testing and publication
Testing on a representative set of devices, store listing preparation, handling Apple and Google reviews, production release.
- 6
Monitoring and evolution
Crash monitoring, compatibility updates for new operating systems, new features based on observed usage.
Technologies we use
- React Native
- Expo
- TypeScript
- Swift
- Kotlin
- Node.js
- PostgreSQL
- Firebase
- Push notifications (APNs, FCM)
- Fastlane
- App Store Connect
- Google Play Console
Related expertise
Why choose Agencei?
The right technical choice, not a default one
We do not push React Native or native systematically: we explain the consequences of each option on cost, performance and maintenance, then decide with you.
Backend and mobile by the same team
We design the API alongside the app, which avoids the inconsistencies and blockers that commonly appear when two vendors share the project.
Store publication and reviews handled
We know the common rejection reasons from Apple and Google and prepare submissions to limit back-and-forth.
An app that stays maintainable after us
Documented TypeScript code, automated tests and a delivery pipeline in place: your team or another vendor can take over without starting from scratch.
In brief
- What is this service?
- Design and development service for iOS and Android mobile apps, native or with React Native and Expo, including backend, app store publication and maintenance.
- Who is it for?
- Companies, software vendors and organizations that want to launch a mobile service, equip field teams or replace an existing app.
- What problem does it solve?
- Giving your users a reliable app, published on both stores, connected to your systems and maintainable over time.
- How long does it usually take?
- From several weeks for a focused first version to several months for a feature-rich app with many integrations, excluding store review times.
- What factors influence the price?
- Number of screens and user journeys, offline requirements, integrations (payment, CRM, connected devices), native versus cross-platform choice and the required level of testing.
- How does the engagement run?
- Scoping, prototype, development in batches with regular test builds, backend development, real-device testing, publication and follow-up.
- What are the risks?
- Store review rejections, an oversized scope for a first release, dependence on poorly maintained libraries, underestimating yearly maintenance.
- What alternatives exist?
- A progressive web app (PWA) if native features are not essential, or a responsive web app if installing on the phone adds no value.
Frequently asked questions
Should we build natively or with React Native?
React Native and Expo cover the vast majority of service and business apps, with a single codebase for iOS and Android. Native remains preferable for apps that depend heavily on hardware, video processing or 3D. We decide after reviewing your key features.
How long does it take to publish a mobile app?
A useful first version usually takes several weeks to a few months depending on the number of screens, integrations and offline requirements. You also need to allow for store review times, which can range from a few hours to several days.
Do you also build the app's backend?
Yes. Most apps need an API, a database, authentication and push notifications. We build these components or connect the app to your existing system.
Who owns the code and the developer accounts?
You do. The Apple Developer and Google Play accounts are created in your name, and the source code is handed over in a repository you control.
What happens after launch?
Apple and Google release new versions of their operating systems every year, which requires regular updates. We offer ongoing support for monitoring, fixes and new features.
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Tell us about your project
Describe your need in a few lines: we come back to you with a first analysis and the next steps.