Mobile development studio · Romania

Mobile apps built to ship — and built to last.

AppStack is a boutique mobile studio specializing in Flutter and native iOS, with Firebase as a full-stack backend. From MVP to regulated healthcare software, we deliver production apps end-to-end.

AppStack — Mobility & Stability
10+
Years in mobile
3+
Years in Flutter
12
Companies shipped for
1M+
App Store users reached
§ 01 · Services

What we build

01

Flutter app development

One codebase, iOS and Android. Production Flutter apps built with Clean Architecture and BLoC — testable, maintainable, fast to evolve.

02

Firebase full-stack

Auth, Firestore, Cloud Functions, push, analytics, hosting. We own the backend so you get features end-to-end, not just screens.

03

Native iOS development

Swift, UIKit, Core Data, Bluetooth, AVFoundation. A decade of native iOS for when the platform demands it — or when Flutter needs deep interop.

04

Legacy migration to Flutter

We move aging native apps to Flutter without breaking production — including offline-first sync and hardware interop, proven in medical software.

05

MVP for startups

From idea to App Store in weeks. A lean, scalable first version with the architecture to grow — not a throwaway prototype.

§ 02 · Selected work

Projects, shipped.

§ 03 · Team

Who you work with

Marius Gutoi, founder of AppStack
Marius Gutoi
Founder & Lead Engineer

Marius has spent 10+ years in mobile — shipping apps across healthcare, food, IoT, navigation, and social, from solo builds to large international agile teams. For the last three years he has specialized in Flutter, pairing it with Firebase to deliver features end-to-end.

Every AppStack project is led with Clean Architecture and BLoC, so the codebase stays testable and evolvable — and every engagement comes with direct access to the engineer writing the code.

FlutterDartSwiftFirebaseBLoCClean Architecturefreezedgo_routerRealmGitHub ActionsCodemagicFastlane

Have an app to build — or rescue?

Tell us about the scope and timing. We reply within one business day with an honest assessment and a quote.

marius@appstack.ro · Bucharest, Romania · Working worldwide, remote-first