Mobile Apps
Properto | Property Radar
Explore property markets, compare areas, analyze rental returns and stress-test real estate scenarios — with your data kept on your device.
- iOS Mobile app
- Source Code
React Native
Mobile app studio · Taking new projects
Your app idea, built and launched.
We build mobile apps for iPhone and Android — from the first sketch to the day it goes live in the stores. A fixed price, a clear date, and one person who answers every question.
- A fixed price agreed before we start
- Your app on both iPhone and Android
- One person to ask, from start to launch
- Projects shipped
- 96+
- Combined experience
- 18y
- Average reply time
- 12h
- Client retention
- 98%
9:41
Your app
Launch day
Live in the App Store
6 weeks
From first sketch to launch
4.9
Store rating
0
Crashes
Design
Build
Launch
This week
- On the App StoreApproved in 2 days
- On Google PlaySame codebase
- Payments workingCards and Apple Pay
- 1,204 sign-upsFirst week live
What we do
One team for the whole product, from store to server.
Six capabilities that cover a product end to end. Most engagements use three or four of them at once.
Available now
Built already, ready to buy
Complete projects you can take over today — full source, documentation and handover included.
€2,290
Mobile Apps
MindAge | Brain Health
Build healthier daily habits, exercise your mind, and follow your brain health journey with simple activities and personalized insights.
- iOS Mobile app
- Source Code
React Native
Mobile Apps
RealOr | Detect & Analyze
Detect, Analyze, and Humanize AI Content — All in One App.
- iOS Mobile app
- Source Code
React Native
Mobile Apps
DANCERO | Dance Analyse Battle
Put your moves to the test. Analyze your performance, challenge dancers, battle head-to-head, and climb the rankings — completely free.
- iOS Mobile app
- Source code
React Native
Mobile Apps
Invoice Manager|SIMPL
Your Go-To Invoice Generator – Invoice Manager | SIMPL! iOS & ANDROID No more paperwork! Manage invoices, sign documents, and convert images to PDFs—all from your phone!
- iOS & ANDROID mobile apps.
- Source Code
React Native
Mobile Apps
Runa: Pronunciation Practice
Record 30 seconds, get scored on nine dimensions of delivery, then drill the sounds you missed. React Native iOS speech coach with no backend to run.
- Full source code + transfer to your Apple Developer account
React Native
SaaS Platforms
FileFly | Share & Upload Files
iOS App + Web App — File Sharing Utility, Credit-Based IAP
- Live iOS app on the App Store
- Source code
React Native CLINext.js & Vercel
Mobile Apps
Lodestone: Metal Detector EMF
Lodestone reads your phone's built-in magnetometer and turns raw magnetic data into something you can act on. No extra hardware. No account. Works offline.
- iOS Mobile app
- Source Code
React Native
Mobile Apps
Speech Analysis | XEMINO
Speak naturally while XEMINO analyzes your clarity, pace, pauses, filler words and confidence in real time — with short, personalized tips to help you improve.
- iOS app
- Source Code
React Native
Why choose us
Small on purpose. Every layer we removed made the work faster.
A senior engineer who writes every line, and a managing director who owns the commercials. No juniors billed as seniors, no ticket queue between you and the code.
Seniors only, no juniors
Every line is written by an engineer with a decade of production experience. Nothing gets delegated to someone learning on your budget.
Replies in under 12 hours
A shared channel with both founders. No ticket queue, no account manager translating your question into a worse question.
No management layers
You pay for engineering, not for a hierarchy. The person who scoped your project is the person who builds and ships it.
Estimates that hold
Fixed scope, fixed range, written down. When something changes we tell you what it costs before we build it, not after.
Performance is a requirement
Lighthouse budgets, cold-start targets and p95 latency goals are written into the scope and verified before launch.
Built for handover
Documented, tested, conventional code. If you hire an in-house team tomorrow, they will not need us to explain it.
How we work
Six steps from first message to production
The same process every time, whether it is a two-week integration or a six-month platform build.
- 01Same day
Discovery brief
You send the problem, the constraints and the deadline that actually matters. Both founders read it — including the engineer who would build it — and reply by email the same working day. No account manager relay, nothing to schedule.
- Problem definition
- Rough feasibility
- Budget range
- 023–7 days
Scope & architecture
We turn the idea into a written scope: user flows, data model, integrations, risks and the parts we recommend cutting from v1.
- Written scope
- Architecture sketch
- Fixed estimate
- 033–10 days
Design & prototype
Interface design and a clickable prototype so decisions get made against something real instead of a description in a document.
- UI design
- Clickable prototype
- Design system
- 041–5 weeks
Build in weekly slices
Two-week cycles with a working build at the end of every week. You get a demo link, a changelog and direct access to us in a shared channel.
- Weekly builds
- Demo environment
- Shared Slack channel
- 051–2 weeks
Test & harden
Automated tests, device matrix runs, load checks, accessibility pass and a security review before anything reaches real users.
- Test suite
- QA report
- Performance budget
- 06Ongoing
Launch & support
Store submission, deploy pipeline, monitoring and alerting. Then a support agreement sized to what you actually need — often a few hours a month.
- Production release
- Monitoring & alerts
- Handover docs
Technologies
A deliberately boring stack
Tools with long support horizons and large hiring pools, so the product outlives the engagement. Novelty is reserved for your product, not your infrastructure.
TypeScript
React Native
Next.js
Swift
Kotlin
Node.js
NestJS
PostgreSQL
MongoDB
GraphQL
Prisma
Redis
TypeScript
React Native
Next.js
Swift
Kotlin
Node.js
NestJS
PostgreSQL
MongoDB
GraphQL
Prisma
Redis
AWS
Firebase
Docker
Terraform
Stripe
RevenueCat
Expo
Tailwind CSS
Framer Motion
Vercel
Sentry
Playwright
AWS
Firebase
Docker
Terraform
Stripe
RevenueCat
Expo
Tailwind CSS
Framer Motion
Vercel
Sentry
Playwright
Languages
- TypeScript
- JavaScript
- Swift
- Kotlin
- Python
- SQL
Mobile
- React Native
- Expo
- SwiftUI
- UIKit
- Jetpack Compose
- RevenueCat
- Fastlane
Frontend
- Next.js
- React
- Tailwind CSS
- Framer Motion
- Radix UI
- TanStack Query
- Zustand
Backend
- Node.js
- NestJS
- Express
- GraphQL
- Prisma
- tRPC
- Temporal
Data
- PostgreSQL
- MongoDB
- Redis
- TimescaleDB
- SQLite
- S3
Cloud & DevOps
- AWS
- Vercel
- Firebase
- Docker
- Terraform
- GitHub Actions
- Grafana
- Sentry
Testimonials
What clients say once the invoice is paid
Unedited apart from length. Most of these people hired us again.
“We had been through two agencies before. The difference here is that the people writing the code are the people in the call. Decisions took minutes instead of a sprint.”
Testimonial 1 of 6
Replies under 12 hours
Tell us what you are building.
Send us the details and you get an automatic confirmation straight away, then a written feasibility read and budget range from one of the founders. All by email, no calls to schedule.
Or email us directly at info@kellosolutions.com