AmsterdamTop App & Web Developers in Amsterdam
Software development for Amsterdam. We build high-performance mobile apps and web platforms for the Netherlands' thriving fintech and martech ecosystems.
App369 is a founder-led software studio based in Miami, Florida. We build custom mobile apps, web platforms and AI features for businesses in Amsterdam and beyond, working remotely on Eastern Time.
- Fiverr
- 5.0 · 126 reviews
- Own product
- Workspace369
- Fixed-price offers from
- $450
Why App369
Why Amsterdam Businesses Choose App369
What Amsterdam teams should know before working with App369.
Serving Amsterdam, Rotterdam, The Hague, Utrecht, and the Randstad region
Focus on fintech and martech
Focus on Dutch regulatory frameworks including AFM compliance and PSD2
What we build
Software Development Services in Amsterdam
From the Zuidas financial district to Amsterdam Science Park, we deliver software that powers the Netherlands' most ambitious digital ventures.
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 Amsterdam 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 Amsterdam 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 Amsterdam 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. Amsterdam 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 Amsterdam and nationwide.
Start Your Amsterdam Project
Fiverr reviews / 95 on app work
What buyers said about working with Simon
“Szymon was able to answer all the questions I had about this project. It was great to walk through all the details with him.”
Rebecca, United States, August 2021. Custom order on Fiverr “The finest person I've ever had to educate me and aid me with my app's launch. When it comes to assisting, he is very friendly, educated, and patient. I would suggest this individual for any job! It surpassed all of my expectations! If I had the option, I would have given more stars. Choose Szymon to help you instead of looking anyplace else; you will not be disappointed. Szymon thank you for all the help!!!”
Dustin, United States, July 2021. Custom order on Fiverr “Excellent client service!!! We talked through messaging and placed a modest order to speak on the phone to discuss more detailed details. I'm looking forward to finishing the project's final stages. It comes highly recommended!”
Dustin, United States, July 2021. Custom order 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)