Bespoke mobile app development

We develop your bespoke mobile app for iOS and Android, usable within a month, on a fixed monthly budget, and keep adjusting it as your business evolves.

Web first, native when your users need it

A mobile app does not have to go through the App Store and Google Play to be used. A Progressive Web App (PWA) opens from a link and installs on the phone’s home screen.

When the need allows, we start with the PWA. The first version is in your users’ hands within a month, and each feature that has been tested and signed off reaches them without waiting for Apple’s and Google’s review.

A native app, on the other hand, installs from the App Store or Google Play and makes more of the phone. When your app needs that from day one, we start in native straight away.

Otherwise, the way the PWA is used shows us what native has to add, for example fuller offline use or better-supported notifications. We then move to a native app for iOS and Android. The data and the server stay the same: nothing starts again from scratch.

For Tortuga Outdoor, a social platform for mountain sports founded in 2024, we worked on the design of its PWA, then on its migration to a React Native app for iOS and Android: the same server, and a single codebase for both mobile apps.

The server of your mobile app (its API) can be the one behind your web business application. If your app connects sellers and buyers, see also our page on marketplace development. If you want to automate a task with artificial intelligence, see our page on automating a process with AI.

If off-the-shelf software already covers your need, and its vendor makes the adjustments you ask for, it remains the simplest choice.

What we develop on the phone

Here are some of the capabilities we have already built into our mobile apps:

  • Offline use: data already loaded stays available without a network.
  • Reliable push notifications.
  • Maps, on the phone as on the web.
  • Sign-in with the same user account on the web, on iOS and on Android.

One app, written once, for iOS and Android

We write the native app once, with React Native and Expo, two open-source tools designed for this, and it runs on iOS as well as on Android. The same server answers the web app, the iOS app and the Android app. A business rule is written and tested once, then applies to all three.

How your app is delivered

We test and sign off every feature before it goes live. If you would rather not delegate this, you test and approve it yourself.

What has been tested and signed off goes live. Every day, you see the application move forward on your acceptance environment.

Every production deployment goes through a continuous deployment pipeline: security, performance, accessibility, everything is verified automatically before reaching production. For the native app, the new version then goes through Apple’s and Google’s review before it is published on the App Store and Google Play.

In production, we monitor the system continuously: availability, response times, errors.

The users of your application work with it from the first month of development, and how they use it determines the next feature or features.

What we have built

A social platform for mountain sports, on the web, iOS and Android

For Tortuga Outdoor, we worked on its Progressive Web App (PWA), then on its native iOS and Android app in React Native and Expo: a single server for all three, offline use, reliable push notifications and maps on mobile. We worked with the founder: we tested the ideas with users before building them, then measured the effect of each feature once it was in production.

More than 600 users on the platform in three months.

A fixed monthly budget, and what belongs to you

The budget is built with you, from your numbers and your objectives: together we set the amount and the problem your application has to solve. Your application is usable within a month of development. From then on, the budget covers its maintenance and evolution for as long as you want, so that it keeps adapting to your business. Invoicing is monthly and fixed, with no surcharge for licences or number of users. You know your exact spend before you start.

The source code, infrastructure, deployment pipeline and documentation are your intellectual property once the first monthly invoice is paid.

The zero-regression guarantee applies from day one. If an accepted and approved feature starts behaving differently after a change, we fix it at no extra cost and we lock the behaviour with an automated test so it cannot come back.

You can terminate the contract in writing at any time, without justification. During the reversibility month, we support your team until they can build, test and deploy without us.

How much does a mobile app cost?

The budget is built with you, from your numbers and your objectives: together we set the amount and the problem your application has to solve. Your application is usable within a month of development. From then on, the budget covers its maintenance and evolution for as long as you want, so that it keeps adapting to your business. Invoicing is monthly and fixed, with no surcharge for licences or number of users. You know your exact spend before you start.

Do I need a native app or a PWA?

It depends on what your users do with their phone. A PWA installs from a link, without going through the App Store or Google Play, and each new version reaches them straight away. A native app goes through these two platforms and gives access to far more of the phone’s functions. If the need allows, we start with the PWA, then move to native as soon as your users need it, as we did for Tortuga Outdoor.

How long does it take to get my app into production?

Your app is usable within a month, as a PWA when the need allows. A native app also goes through Apple’s and Google’s review before it is published, and that delay is outside our control.

Can my app work without an internet connection?

Yes, for data already loaded: it stays on screen without a network. For Tortuga Outdoor, we worked on setting up this offline use in the native app.

Who publishes my app on the App Store and Google Play?

We prepare each version and submit it to Apple and to Google. The app is published under your company’s developer account.

Does the code of my app belong to me?

The source code, infrastructure, deployment pipeline and documentation are your intellectual property once the first monthly invoice is paid. During the reversibility month, we support your team until they can build, test and deploy without us.

What happens during the trial period?

In the first month, the first 15 working days are a trial period. Delivered features are accepted as they come in, by you or by us if you delegate acceptance to us. If you do not want the deliverables and do not wish to continue, no invoice is issued and you owe nothing. If you want your application in production before the trial period ends, you can ask us in writing: we issue the invoice for the days worked, and we release to production once it is paid.

Who looks after the maintenance of my app?

Corrective, adaptive, preventive and enhancement maintenance is included in the same model. At DEVEDANOS, the same team develops, tests, deploys and maintains your software continuously, in the same pipeline.

Expertise

Which app do you want to see on your users’ phones?

Thirty minutes to understand your situation. If we can help, a second meeting takes place within 48 hours to build the quote together.

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