Mobile Apps
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.
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
Mobile Apps
PERSO | DNA Analytics
Discover your visual heritage profile from a single photo. Explore ancestry-inspired estimates, regional similarities, and personalized insights.
- iOS app
- Source Code
React Native
Mobile Apps
PetCare | Daily Reminder
You take care of your pet. We remember when.
- iOS app
- source code.
React Native
Mobile Apps
Spark: Dating Assistant
Spark is a dating coach, not another swiping app. It works with the apps you already use.
- iOS app
- Source Code
React Native
Mobile Apps
WineGuide | Taste
Discover what’s in your glass. Scan wine bottles, explore pairings, ask your Sommelier, and build your personal wine list.
- iOS app
- Source Code
React Native
Mobile Apps
BREATHING | Calm & Focus
Take a moment to breathe. Calm your mind, prepare for sleep, improve focus, and reset with simple guided breathing exercises.
- iOS app
- Source Code.
React Native
Mobile Apps
EcoScan AI : Product Scanner
Track CO₂ & Eco AI-powered
- EcoScan AI : Product Scanner iOS app.
- Source code.
React Native
Mobile Apps
Pixly – Storage Cleaner
Pixly helps you free up storage by finding duplicate photos, screenshots, large videos, and contact duplicates, with easy one-tap cleanup tools.
- Pixly – Storage Cleaner 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