New YorkTop App & Web Developers in New York
Software development for NYC. We build scalable mobile apps and web platforms for Manhattan businesses and beyond.
App369 is a founder-led software studio based in Miami, Florida. We build custom mobile apps, web platforms and AI features for businesses in New York and beyond, working remotely on Eastern Time.
- Fiverr
- 5.0 · 126 reviews
- Own product
- Workspace369
- Fixed-price offers from
- $450
Why App369
Why New York Businesses Choose App369
What New York teams should know before working with App369.
Serving Manhattan, Brooklyn, Queens, and the tri-state area
Focus on NYC's fast-paced business environment
Focus on fintech, media, real estate, and enterprise software
Understanding of New York's regulatory requirements
What we build
Software Development Services in New York
From Wall Street to Silicon Alley, we build software that meets the demands of New York's most ambitious businesses.
Mobile Apps
iOS and Android apps built with Flutter from one codebase, from concept to App Store launch.
- iOS & Android
- Cross-Platform
- App Store Optimization
- Maintenance & Updates
Web Development
Fast websites and web applications, built for search and for phones first.
- Custom Design
- E-Commerce
- SaaS Applications
- SEO Optimization
Custom Software
Internal tools, integrations and back-office systems engineered around how your team already works.
- Enterprise Development
- API Integration
- Cloud Migration
- Technical Consulting
How it works
Our 4-Phase Development Process
A written scope and four clear phases keep New York projects predictable.
Discovery
Understanding your vision, goals, and market requirements through stakeholder interviews and competitive analysis.
Design
Creating clear UI/UX with interactive prototypes you can click through before we build.
Development
Building with Flutter, Vue.js, Node.js, and GCP using 2-week Agile sprints with weekly milestone reviews.
Launch
Deployment to production with crash and uptime monitoring and ongoing maintenance.
Technologies
- Flutter
- TypeScript
- Node.js
- GCP
- Firebase
- Vue
- JavaScript
- Python
Questions
Frequently Asked Questions
How long does a typical project take?
It depends on scope. As a rough guide, a marketing website takes 4-8 weeks, a web application 2-4 months, and a mobile app 3-6 months. Every New York project starts with a written scope and milestone plan, so you know the timeline before any build work starts.
Do you provide ongoing support?
Yes. After launch we offer maintenance that covers bug fixes, iOS and Android OS updates, security patches, dependency upgrades and small feature work, so your New York app keeps working as the platforms change.
What's your pricing model?
App369 uses project-based pricing with a 50/50 payment structure: 50% upfront and 50% on completion. Current ranges are published on our fee structure page, and smaller fixed-price packages are available for well-defined work.
Can you work with existing projects?
Yes. We take over existing codebases, especially Flutter and Firebase apps, for code audits, bug fixes, new features and migrations. New York businesses with an app that stalled or a developer who left can start with an audit before committing to a larger build.
What technology do you use?
Mostly Flutter for iOS, Android and web apps from one codebase, Firebase and Google Cloud for backends, and Vue/Nuxt for websites. For AI features we integrate large language models for assistants, document extraction and automation.
Your Development Partner
Simon Dziak
As founder of App369, I personally oversee every project we take on, from scoping to launch. I build with Flutter, Firebase and Google Cloud, and I also built and run Workspace369, a client-management platform for freelancers and small businesses. Based in Miami, Florida, we serve clients across New York and nationwide.
Start Your New York Project
Fiverr reviews / 95 on app work
What buyers said about working with Simon
“Szymon explained to me in detail the steps of the project. I appreciate his honesty and patience in explaining his service to someone like me who does not understand most technical lingo. I highly recommend his service!”
A buyer in the United States, May 2021. App development on Fiverr “Amazing work! I love working with Szymon. He is proactive, intelligent, and creative! If you need any app development, you should definitely shoot him a message! The whole process was spectacular!”
Mark, United States, May 2021. App development on Fiverr “Outstanding work! He went above and beyond to make an amazing app for me! I will definitely be working with Szymon again!”
Mark, United States, April 2021. App development on Fiverr
Read the whole story
- Sixteen five-star reviews from one buyer: mobile apps, app design and a Shopify store (Mark, United States)
- A large custom app build, delivered on the back end and the front end (A buyer in the United States)