Androidapp development services built in Kotlin, tested on real devices

We build native Android apps that stay fast and stable across the phones your customers actually own, from flagship devices to budget models with little memory.
Discuss your Android app

Android is not one device. It's thousands of them.

Your app has to work on different screen sizes, manufacturers, Android versions and network conditions. A build that looks perfect on the developer's phone can crash on a cheaper one. We write Kotlin apps with that reality in mind and test them on a broad set of devices before every Google Play release.

Why Android apps are hard to get right

01

Device fragmentation

Manufacturers change system behavior, screen sizes vary widely and older Android versions stay in use for years.
02

Crashes you can't reproduce

Bugs appear only on certain models or OS versions, and the team doesn't have those devices on the desk.
03

Google Play policy changes

Target API requirements, permission rules and data safety forms change regularly. Missing one can block your next update.
04

Background work gets killed

Battery savers stop syncs, notifications and location updates differently on each brand.
05

Old Java code holds you back

Legacy Java and XML layouts make every new feature slower to build than it should be.
06

Android gets second priority

Many teams build iOS first, and the Android app lags behind in features and quality.

Where Android apps usually break

These are the problems we look for first, whether we build the app or take it over.

Fragmentation

  • Layouts that break on small or large screens
  • Behavior that differs by manufacturer
  • Features missing on older Android versions

Stability

  • Crashes on low-memory devices
  • Lost state after rotation or backgrounding
  • Unhandled network errors

Performance

  • Slow cold start
  • Janky lists and animations
  • Heavy battery and data use

Store compliance

  • Outdated target API level
  • Permissions without clear justification
  • Incomplete data safety details

Signs your Android app needs expert help

If you recognize a few of these, the app needs more Android focus than it's getting.

1

Play Store rating is lower than iOS

Same product, worse reviews, and most complaints mention crashes or slowness on specific phones.

2

Most of your users are on Android

Your market leans to Android, but the app doesn't feel built for it.

3

A Google Play warning arrived

You got a policy or target API notice and aren't sure what has to change or by when.

4

Features ship to iOS first

Android users wait weeks or months for what iPhone users already have.

5

The codebase is still mostly Java

Developers avoid touching old modules and estimates keep growing.

6

You need Android-specific features

Home screen widgets, background sync, NFC, Bluetooth or deep integration with other apps.

What we build

Android development services we provide

New Android apps

Native Kotlin apps with Jetpack Compose, from first prototype to Google Play launch.

Tablet and foldable layouts

Adaptive screens that use large displays instead of stretching a phone layout.

Android UI/UX design

Material Design patterns adapted to your brand and your users' habits.

Java to Kotlin migration

Moving old Java and XML code to Kotlin and Compose module by module.

APIs and integrations

Backend APIs, payments, maps, analytics, push notifications and third-party SDKs.

Offline and background work

Reliable sync, caching and background tasks that survive battery optimizations.

Device testing

Automated tests plus manual checks across screen sizes, brands and Android versions.

Google Play release

Signing, staged rollouts, store listing and policy forms handled for you.

Our Android technology stack

Modern Android tooling for the app, with the backend and cloud pieces it needs.

Kotlin
Android Studio
GitHub Actions
CircleCI
Node.js
Python
PostgreSQL
AWS
Docker
Who is this for

Companies whose customers carry Android phones

Startups in Android-heavy markets

Your users are mostly on Android and the app has to work well on mid-range phones.

Product companies

Your iOS app is ahead and the Android app needs to catch up and keep pace.

SMBs with field teams

Couriers, technicians or sales reps use rugged or company-issued Android devices every day.

E-commerce and fintech apps

Payments, logins and checkout have to work on every device your customers own.

Where can we help?

Launch on Android

A native app from design to Google Play release.

Reach parity with iOS

Close the feature gap between your two apps.

Cut crash rates

Find and fix device-specific crashes.

Modernize the code

Move from Java and XML to Kotlin and Compose.

Meet Play policies

Target API updates, permissions and data safety.

Extend your team

Kotlin engineers inside your existing team.

How we build and release your Android app

01

Discovery

We define users, core flows and the device range you need to support, using your analytics where they exist.

02

Design

Screens and flows designed for Android patterns, with adaptive layouts for tablets where they matter.

03

Development

Kotlin engineers ship features in short sprints, with internal test builds you can install on your own phone.

04

Device testing

QA covers the brands, screen sizes and Android versions in your device matrix.

05

Google Play release

Staged rollout, store listing and policy forms, with crash monitoring during the first days.

06

Support

New features, Android version updates and Play policy changes handled as they come.

How we work

Pick how to start

Fixed-scope build

most popular

Starts with a 2-week Discovery Sprint

Fixed price after discovery.

For a new Android app or a clearly defined set of features.

Agreed scope, timeline and cost

Design, Kotlin development and QA

Device matrix agreed up front

Google Play release included

Hand-over or ongoing support after launch

Plan your app

Android team extension

Kotlin engineers join your team

Monthly, per engineer.

For teams with an Android app and more work than people.

Senior Kotlin and Compose engineers

You interview and choose each one

Your backlog, tools and rituals

Help with Play policies and releases

Change team size as needed

Add Android engineers

Android and mobile projects we've delivered

FinTech

Android application for FinTech industry

Read the case study →
Pharmacy · DACH

Redesigning and modernizing an Online Pharmacy mobile app

Read the case study →

Make the most of the experienced team

We are a global team of
creative
and
strategic thinkers
who specialize in building custom digital products
from scratch. Our main goal is to
deliver high-quality solutions
that meet our clients' needs.
We are a global team of
creative
and
strategic thinkers
who specialize
in building custom digital products
from scratch. Our main goal is to
deliver high-quality solutions
that
meet our clients' needs.
Learn more
85%
recurring customers
12M
the biggest fundraising round by one startup
X3 MRR
growth of partner's business in 5 mos
2 weeks
for project start
5+ years
av. partnership duration with SMBs and product companies

Why Gilzor

Android is a first-class platform for us, not a port of the iOS app. We plan for the devices your users own and keep the app healthy after launch.

What we bring

Mobile experience

7+ years building iOS and Android products.

Launch track record

70+ products launched for our clients.

Predictable delivery

98% of projects delivered on time.

Long-term partner

85% of our customers come back with new work.

Full team

Design, Android, backend and QA from one partner.

What makes us different

Real-device testing

We test on the phones your users have, not only on emulators.

Kotlin first

Modern Kotlin and Compose for new code, with a plan for old Java.

Policy awareness

We track Google Play changes so your updates don't get blocked.

Parity mindset

Android users get the same product quality as iPhone users.

Overlap with US hours

Our engineers in Europe overlap with part of the US working day.

What our clients
frequently ask

How do you deal with Android device fragmentation?

We agree a device matrix based on your analytics or target market, build with adaptive layouts, and test on real devices across brands, screen sizes and Android versions before each release.

Do you build new apps in Kotlin or Java?

Kotlin, with Jetpack Compose for the UI. If your app is in Java, we can keep maintaining it and move it to Kotlin gradually, starting with the modules you change most.

Will you publish the app on Google Play?

Yes. We prepare the build, listing, content rating and data safety details, and use staged rollouts so problems show up before every user gets the update. The app stays in your own Play Console account.

Our iOS app already exists. Can you build the Android version?

Yes. We study the iOS app, reuse your backend and design where it fits, and adapt the experience to Android patterns so it doesn't feel like a copy.

Should we go native Android or cross-platform?

Native Kotlin fits apps that depend on device hardware, background work or top performance. If you need both platforms with one team and a shared codebase, React Native or Flutter may suit you better. We'll give you an honest recommendation.

How is Android development priced?

A new app usually starts with a 2-week fixed-price Discovery Sprint, then a fixed price for the agreed scope or a monthly team. Adding engineers to your team is billed monthly per engineer.

No sales pitch

Tell us about your Android app

Share your plans or your current app, the devices your users have and your timeline. We'll reply with questions and a suggested approach.

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