Long Island App Developer
Native-quality iOS and Android apps, built by one engineer who designs, codes, and ships the whole thing — fast, polished, and made to last on the App Store and Google Play.
I’m Ken Key, a Long Island app developer who builds mobile apps end to end — from the first sketch to a live listing on the App Store and Google Play. Most apps fail not because the idea was wrong, but because they were assembled by a rotating cast of contractors with no one accountable for how the whole thing felt. I work the opposite way: one engineer who designs it, codes it, and ships it.
I build cross-platform with React Native and Expo so a single, well-engineered codebase runs natively on both iOS and Android — and I reach for native Swift when a project genuinely calls for it. Push notifications, in-app purchases, sign-in, real backends and APIs — wired in properly, not bolted on. It’s the same way I build the apps behind KeyInventions. Whether you’re a Long Island business that needs an app or a founder with an idea and no technical co-founder, you get something that feels native, loads fast, and you’re proud to put in someone’s hand.
What an app build includes
iOS & Android from one codebase
React Native and Expo for a single, maintainable codebase that runs natively on both stores — plus native Swift when a project demands it.
Designed and built by one person
No agency handoffs or lost-in-translation specs. The person who designs your app is the one who codes and ships it.
Push, payments & real backends
Notifications, in-app purchases, authentication, and APIs built in properly — the parts that make an app actually useful.
Launched, not just built
App Store and Google Play submission, review, and the ongoing updates that keep an app alive as the OS moves under it.
A simple, honest process.
Understand
We talk through what you’re actually trying to achieve. If I’m not the right fit, I’ll say so and point you somewhere better.
Build
I design and build it properly, keep you in the loop, and make the trade-offs visible instead of hiding them.
Last
You get something fast, documented, and maintainable — and I’m here when you need to grow it.
You get the person building it, not a project manager.
You talk to the person writing the code
No account managers, no game of telephone. The person who scopes your project is the one who builds it, and the one you email when something needs to change.
One person accountable for all of it
Design, code, performance, and the search foundation underneath. Nothing falls through the gap between a design team and a dev team, because there is no gap.
Senior work, priced like an independent
No agency overhead of offices, sales teams, and layers of management. You get experienced hands at a fair rate, and decisions happen in a conversation instead of a change-request queue.
Frequently asked.
How much does it cost to build an app?
It depends entirely on scope — a focused MVP is a very different project from a full platform with accounts, payments, and a backend. After a short conversation about what you actually need, I’ll give you an honest, fixed range. No padded retainers.
iOS, Android, or both?
Both, usually from one codebase. I build cross-platform with React Native / Expo so a single build ships to the App Store and Google Play — which keeps cost and maintenance down. When a project needs deep native iOS work, I build in Swift.
Can you take my app from idea to the App Store?
Yes — that’s exactly the kind of work I like most. Idea, design, build, store submission, and launch, with one engineer accountable for the whole thing.
Do you maintain apps after launch?
Yes. Apps aren’t “done” at launch — iOS and Android change every year. I keep apps current, fix issues, and add features as you grow.
How long does it take to build an app?
A straightforward app can reach the App Store in a couple of months, and something more complex takes longer. I scope it honestly up front, build in stages, and get a testable version in your hands early so your feedback shapes the product.
Explore more of what I do
Working across Suffolk & Nassau.
Based in Commack and working with businesses all over Long Island — and remotely beyond. If you searched “app developer near me,” you’re in the right place.
Have an app idea worth building?
A few sentences about your project is all it takes to start.