Custom mobile app agency for iOS & Android
A custom mobile app, built primarily with Expo / React Native, delivered from wireframe to store in a few months with the design and performance that keep your users coming back. A senior iOS and Android team, from scoping to release on the App Store and the Play Store.
How do you build a custom mobile app?
Building a custom mobile app goes through three steps: choosing the right framework for your target and budget (Expo / React Native first, native Swift/Kotlin or Flutter when the context calls for it), designing the journeys with high-fidelity mockups tested on device, then developing in short sprints up to publication on the App Store and the Play Store. We guide you from start to finish.
Why isn't a mobile app just a responsive website?
Mobile users expect a smooth experience, integrated with the OS, sometimes available offline. A poorly designed app gets uninstalled as fast as it gets installed.
Insufficient performance
Stuttering animations, slow screens: 70% of uninstalls come from an app that's too slow or too heavy.
iOS and Android fragmentation
Screen sizes, OS versions, permissions: covering the whole mobile ecosystem takes time and requires experience.
Store publication underestimated
App Store review, Play listing, screenshots, updates: a project in itself that most teams don't master.
From prototype to store, without friction
We start from your use case, build primarily with Expo / React Native, or the framework that makes sense for your budget and target, deliver a usable MVP quickly, then enrich it at the pace of user feedback.
The right framework for your project
Expo / React Native is our go-to stack for most apps. Native if performance is critical, Flutter when the context calls for it: we choose based on your constraints, not our habits.
A UX that respects each OS
We follow Apple's guidelines and Material Design. Your users feel at home, whatever their platform.
Stores handled end to end
Developer accounts, listings, screenshots, reviews: we take care of the entire publication process up to going live.
How do you keep users on your mobile app?
We aim for the right KPIs: store rating, retention, conversion. Not just an MVP that ships.
The right tech for your case
Our go-to stack: Expo / React Native. Flutter or native when your case calls for it, we choose based on your target and budget, not our preferences.
An MVP in a few weeks
From wireframe to TestFlight and Play Internal Testing quickly. You test with real users before the public release.
Top-tier performance
60 fps, fast startup, offline handling: we treat performance as a feature in its own right.
Stores handled for you
Developer accounts, listings, screenshots, App Store and Play Store reviews: we take care of everything.
Our mobile app expertise, in numbers
What we build to measure
Technologies
The technologies we use for your app.
How do we build your custom mobile app?
Discovery & framework choice
User target, key journeys, budget constraints: Expo / React Native first, native or Flutter when the case calls for it.
Clickable prototype on device
High-fidelity mockups tested on a real device before writing a single line of code.
Short sprints and regular builds
Weekly demos, builds distributed via EAS, TestFlight and Play Internal Testing.
Publication and follow-up
App Store and Play Store submission, crash monitoring, continuous updates.
Our success stories
Here, our clients share their journey, what they went through and what the collaboration helped them achieve.
We're working with Fragments Studio on the development of Smart Interview, and the experience is excellent. The team quickly grasped our product vision and turned it into a concrete, structured, high-performing solution. Strong technical level, real advisory ability, responsiveness and an eye for detail. Beyond development, they challenge ideas, suggest relevant improvements and move forward with a genuine spirit of partnership. A serious, committed and results-driven studio. I highly recommend them.
Adrien LenoirManaging Director
You put me at ease, that's the word that comes out of working together. We can rely on you, your experience, your know-how. This site is the fruit of that whole journey together, the reflection of serious work full of trust.
Zeina EghoFounder
We had the pleasure of working with Fragments Studio on a specific specialty and we were not disappointed. Talented and committed, their responsiveness and team spirit were major assets in the success of this ambitious project. Technical expertise that met our expectations thanks to their mastery of the technologies used. A smooth and proactive collaboration, with results that matched our ambitions. We recommend them without hesitation! For any company or team looking for skilled, reliable and invested developers, we warmly recommend Fragments Studio. A partner of choice for all your IT projects. Contact them without hesitation.
Christophe HouetIT Project Manager
Working with Fragments Studio was a great experience. They helped me automate part of my prospecting that was taking up a lot of time, with simple and effective solutions. I particularly appreciated their responsiveness and the fact that they always suggest new ideas to improve things. It's a young, dynamic and very approachable team, which makes the collaboration smooth and enjoyable.
Lucie DercksenStrategic Partnership
The team is efficient, proactive and accountable. They quickly understand the needs and the stakes. A project delivered ahead of schedule and with a high level of quality!
Victorien DefosseCEO
A top-notch team. Available, responsive and genuinely attentive! You understood the project and made it your own to address it properly. The dialogue is smooth, simple and effective, which makes the collaboration really enjoyable. The deliverables are high quality and, above all, delivered on time. Thank you for your commitment! I recommend without hesitation.
Diamil GaultierFounder
A great experience with this agency. Attentive, involved and very professional, the team turned a vision into a clear, premium and effective site. The exchanges were smooth and the deadlines were met. A real partner, not just a vendor.
Théo VassouxFounder
Fragments Studio helped us build a robust platform that scales perfectly. Their technical expertise and strategic thinking made all the difference.
Kevin JehuCEO
Fragments Studio helped me structure my project on a solid footing, supported me effectively through the launch and gave me the keys to get started in the best possible conditions. Their perspective, their method and their support were decisive in the first steps of my entrepreneurial journey.
Pierre EscofetFounder
Exchanges with Fragments Studio are smooth, efficient and friendly. Particular attention is paid to responsiveness, both in handling requests and in the time taken to reply. Interactions take place in a pleasant, warm atmosphere.
Philippe ProvotPayroll managerThe budget for a custom mobile app depends on the scope and the chosen framework. An Expo / React Native or Flutter MVP is accessible far sooner than a full native app. We scope your needs upfront and give you a clear estimate before starting. The price is almost always offset by the value generated within the first few months.
Expect 10 to 16 weeks between the brief and the first public release. We aim for an MVP testable via TestFlight and Play Internal Testing within a few weeks, then publication once user feedback is integrated. The initial scope is the most important variable.
It all depends on your case. Native (Swift / Kotlin) remains unbeatable for demanding apps like games or augmented reality. For the vast majority of custom mobile apps, we build with Expo / React Native: real savings in cost and time, with EAS Build and OTA updates. Flutter remains an option when the context calls for it. We guide you without dogma, based on your target and your stack.
Look for an agency that understands your business before talking tech, that masters Expo / React Native and has work published on both stores, and that gives you an honest estimate. At Fragments, we systematically scope the project before any commitment and steer you toward the framework that fits your budget and timeline.
Yes. We handle the Apple Developer and Google Play accounts, listing preparation, screenshots, and all submissions through to approval. You remain the owner of the accounts and the code.
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Let's talk about your mobile app
30 minutes to scope your project and choose the right mobile stack, in practice Expo / React Native for most projects.
Scope my app