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Mobile app developmentBuild your mobile app for iOS and Android

Tell us what your app should do. App369 designs and builds it, then submits it to the App Store and Google Play from your own developer accounts. Based in Miami, Florida.

Under the hood: Flutter for one codebase on iPhone and Android, or Swift for iPhone-only apps, with Firebase or a Node.js backend on Google Cloud.

See my price Tell us about your app
Two smartphones on a dark studio floor, each showing a simple app layout with a light blue button
Fiverr
5.0 · 127 reviews
Own product
Workspace369
Fixed-price offers from
$450

Prefer a fixed price?

Fixed scope, fixed price, paid upfront. The work happens in writing; no call needed.

Meet Simon

How we build your app, in 60 seconds

Simon, App369's founder, on the written scope, the fixed price, test builds on your phone and the launch.

What we build

Full-stack mobile services

01

Cross-Platform Flutter Development

Build one codebase that runs on both iOS and Android.

02

User-Centric Design

Our design process combines user research, interactive Figma prototypes, and usability testing to create interfaces that convert.

03

Scalable Cloud Architecture

Our architecture supports real-time data sync, push notifications, and auto-scaling infrastructure.

04

Secure & Compliant

Security aligned with OWASP Top 10 guidelines. We implement end-to-end encryption, biometric authentication, and HIPAA-compliant data handling where required.

How it works

Our process

  1. Discovery & Planning

    We start by understanding your business goals, target audience, and app requirements to create a comprehensive development plan.

  2. UI/UX Design

    Simon designs intuitive, engaging interfaces that align with your brand and provide exceptional user experiences.

  3. Development

    Simon builds your app in Flutter, Swift or Kotlin, with automated tests and a build pipeline, and shares progress in writing.

  4. Testing & QA

    Rigorous testing across devices and platforms to ensure your app is bug-free, secure, and delivers a reliable experience.

  5. Deployment

    We handle the app store submission process and ensure your app meets all requirements for successful launch.

  6. Maintenance & Support

    Ongoing support, updates, and enhancements to keep your app running smoothly and evolving with your business needs.

Technologies

  • Flutter
  • Swift
  • Kotlin
  • Firebase
  • Google Cloud
  • TypeScript
  • Vue
  • Node.js

Error fixes

App Store rejections we fix

Each page explains the rejection from Apple’s own guidelines, with what to change before you resubmit.

Error fixes

Google Play problems we fix

Each page explains the problem from Google Play’s own help pages, with what to change next.

Questions

Frequently asked questions

How much does it cost to develop a mobile app?

Cost depends on scope, platforms and integrations. Our rates are published on the fee structure page, and the free app cost calculator gives a range for a mobile app with every assumption listed. We send a fixed quote after reviewing your brief.

How long does it take to build a mobile app?

Simple apps with core features take 2-3 months, medium-complexity apps with backend API integration and user management require 3-6 months, and complex enterprise applications with real-time features and CI/CD pipelines can take 6-12 months.

Should I build for iOS, Android, or both?

Building for both platforms maximizes your addressable market.

What is Flutter and why do you use it?

It compiles to native ARM machine code for both iOS and Android, delivering 60fps performance with a single Dart codebase.

Do you provide ongoing maintenance and support?

Yes. App369 provides comprehensive post-launch support including bug fixes, OS compatibility updates for new iOS and Android releases, security patches, performance monitoring via Firebase Crashlytics, and feature enhancements. Our maintenance packages include CI/CD pipeline management and automated regression testing.

Can you help with app store submission?

App369 handles the entire submission process for both Apple App Store and Google Play Store. Simon prepares all required assets, writes ASO-optimized descriptions, and ensures compliance with the latest Apple Human Interface Guidelines and Google Play Store policies. We also set up TestFlight for iOS beta distribution and Google Play's internal testing tracks.

Data and research

Start here

Launch your app in 3-6 months

Whether you need an MVP or an enterprise platform, get a detailed estimate by email, usually within one business day, or book a consultation ($100 per 15 minutes, paid upfront).

Get in touch View pricing

Fiverr reviews / 95 on app work

What buyers said about this kind of work

Read 126 of the 127 reviews
  • “Thank you again, Simon, for another QUICK and SATISFACTORY delivery! I highly recommend this seller because he is fantastic! I'm also coming back to buy more services. My requests were a bit over the roof, but his understanding of the task is mouthwatering. Once I saw his delivery, I approved it immediately. And he was very responsive while discussing the details.”
    Mark, United States, March 2022. App development on Fiverr
  • “Incredible professional! I am really excited to be working with him on my new application. He will take the time to really understand what your project needs. Simon is the best!”
    Mark, United States, March 2022. Custom order on Fiverr
  • “Szymon is very professional, attentive to detail, and organized with his work. I appreciate the help with my project and I will be looking forward to our continued work together. THANK YOU!!!!”
    A buyer in the United States, January 2022. Custom order on Fiverr

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