How much does app development cost?

It is quoted. The price depends on the number of screens, the features, user accounts and links with your other tools. After a first exchange and a scoping step, you get a firm price.

How long does it take to build an app?

Based on the scope, we give you a firm timeline in the quote. A simple first version ships sooner. We then add features in stages.

Web app, PWA or mobile app: which one?

A web app works everywhere. A PWA also installs on the phone, without the stores. A native app makes sense if you need deep access to the phone or a presence in the stores. We advise you before we start.

You do. The code, the data and the accounts are in your name. You can hand the project to another team at any time.

Can you take over an existing app?

Yes. We start with an audit of the code and of usage. Then we suggest fixing, improving or rebuilding.

Do you handle maintenance after launch?

Yes. We offer a monthly follow-up: fixes, security updates and small improvements. It is set in the quote.

Do you work with companies outside Nice?

Yes. We work remotely with companies across France. Meetings happen by video call.

Web and mobile app development agency.

You have an app idea, or a tool that no longer keeps up. We design, build and launch it. One team, from scoping to follow-up, for companies across France.

Describe my project Free audit of your website

What we build.

Business apps: tracking orders, files, stock or field work.
Client portals and portals for your partners.
SaaS platforms, with accounts, subscriptions and online payment.
Mobile apps for iPhone and Android.
Internal tools that replace spreadsheets and email threads.
Web games and experiences, for a brand or an event.

Web, mobile or PWA: the difference, simply.

A web app opens in the browser, on a computer or a phone. There is only one version to build and maintain. Updates reach every user right away.

A PWA (progressive web app) is a web app that installs on the phone's home screen. It opens like an app, without going through the App Store or Google Play. It can partly work offline.

A native mobile app is published on the App Store and Google Play. It makes sense if you need deep access to the phone (sensors, Bluetooth, background tasks) or a presence in the stores. It means following two platforms and passing Apple's and Google's review.

We advise you before we quote. Often, a web app or a PWA is enough to start.

Our apps are live.

They are our proof. You can open and try them. Bien en règle, Color Guesser and Bilber are our own products: we designed, built and launched them ourselves.

Bien en règlebienenregle.com
A web app on holiday rental compliance, city by city. Online check, PDF report, built-in payment.
Color Guesserplaycolorguesser.com
A web game translated into 7 languages. Fast on phones, playable without an account.
Bilberbilber.app
A SaaS platform to create digital product passports.
PerPostperpost-web.vercel.app
A website and its app.

See all our work

How a project runs.

A first exchange, in writing or by video: the need, the users, the constraints.
A written scope: screens, features, what goes in the first version and what waits.
A quote with a firm price and timeline, based on the scope.
Mock-ups to approve before code, to avoid surprises.
Development in stages, with a test version you open whenever you want.
Launch, then follow-up: fixes, improvements, usage tracking.

Read the article (in French): the steps of a custom build

Across France, remotely.

We are based in Nice. Workshops and reviews happen by video call, with a shared test link. You see the app progress, wherever you are.

On the French Riviera? We also come to you.

App development in Nice

The code is yours.

We build on solid, widely used tools: Next.js and React for the interface, a Postgres database for the data, Stripe for payments, Vercel hosting. Other teams know how to take them over.

The code, the data and the accounts are in your name. If you ever change provider, you leave with everything.

Already have an app?

We can start with an audit. You will know what works, what blocks your users and what to rebuild first.

Request the audit

An app, and customers to use it.

An app must be found. We also work on the site that presents it, on search and on the campaigns that bring the first users.

Frequently asked questions

How much does app development cost?
It is quoted. The price depends on the number of screens, the features, user accounts and links with your other tools. After a first exchange and a scoping step, you get a firm price.
How long does it take to build an app?
Based on the scope, we give you a firm timeline in the quote. A simple first version ships sooner. We then add features in stages.
Web app, PWA or mobile app: which one?
A web app works everywhere. A PWA also installs on the phone, without the stores. A native app makes sense if you need deep access to the phone or a presence in the stores. We advise you before we start.
Who owns the code?
You do. The code, the data and the accounts are in your name. You can hand the project to another team at any time.
Can you take over an existing app?
Yes. We start with an audit of the code and of usage. Then we suggest fixing, improving or rebuilding.
Do you handle maintenance after launch?
Yes. We offer a monthly follow-up: fixes, security updates and small improvements. It is set in the quote.
Do you work with companies outside Nice?
Yes. We work remotely with companies across France. Meetings happen by video call.

Let's talk about your project.

A few lines are enough. We come back with a proposal and a quote.

Describe my project

contact(a)troiestudio.fr