MJ

Marcin Jędrzejak

Available to hire

I’m an iOS Developer who ships products end-to-end: from idea and UI design, through implementation to App Store release and ongoing iteration.

About

I’m an iOS Developer who ships products end-to-end: from idea and UI design, through implementation to App Store release and ongoing iteration.

I have built and maintain multiple SwiftUI apps, including:

  • PillMemo: Medication reminders with Core Data/CloudKit, notifications, in-app purchases, automated tests and CI with Xcode Cloud
  • MedScan: AI-powered medicine analysis using GPT-4 Vision plus a backend and custom UI components
  • AquaVibe: Journey to a more mindful, hydrated and emotionally balanced life, using State of Mind and HealthKit API to save mood, emotions and water intake
    data
  • ShotDocu: Multi-page PDF creation from photos/scans using PDFKit and CloudKit

My work has real product and growth outcomes, including #1 and Top 10 rankings in the US for selected keywords (ASO).

I use proven architectures (MVVM/VIPER), focus on reliability (error handling, testing, clean code) and deliver critical features that must be stable (sync, payments, notifications).

I combine engineering with product thinking: analytics (TelemetryDeck/Mixpanel/Aptabase), data-driven decisions, and fast iteration without sacrificing quality.

If you need a solid MVP or want to improve and scale an existing iOS app, I deliver predictably and efficiently.

  • Joined February 2026

Skills· 2

Languages

  • EnglishIntermediate
  • PolishFluent

Industry experience

  • Software & Internet

More experts in Bydgoszcz, Poland

Projects · 4

💊 PillMemo

https://www.twine.net/signin

PillMemo is an easy-to-use application that helps users remember to take their medicine 🏥

The application allows users to set reminders for different types of medicine and at different times of the day/week/month 📅

👨‍💻 Technology Used

  • SwiftUI
  • Core Data
  • CloudKit
  • User Notifications
  • UICalendarView

🎥 PillMemo ‘in action’

https://www.twine.net/signin

🏆 My standout success is…

Distinguish to save pill data with and without notifications.

Sounds trivial, but the real challenge was to create functionality to save pill data in Core Data and be read correctly by app, where each pill needed to be unique. Why? Because earlier, every next pill was saved, but remembered with the same reference, for the same date, where for the same date can be taken more than one pill. Without this change, app crashed every time when I wanted to save new pill with the same exact date.

🧩 Entireness

Nevertheless, while creating this simple medicine reminder app, I have also included the following:

  • In-App Purchases
  • TipKit
  • WishKit
  • Concurrency
  • Error handling & alerts
  • Onboarding
  • PDF Generator
  • Unit Tests
  • UI Tests
  • CI/CD (Xcode Cloud)
  • Project organization (VOODO Architecture)
  • Privacy Manifest
  • Published in App Store (04/2024)

ℹ️ License

The PillMemo is the property of Marcin Jędrzejak. Unauthorized copying, distribution, or modification of this application is strictly prohibited.

®️ 2026 All rights reserved by Marcin Jędrzejak.

💊 PillMemo
  • Developer

https://www.twine.net/signin

https://www.twine.net/signin

MedScan is an iOS app for identifying medications. Take a photo of a medication’s packaging, and the image recognition system suggests the medication. After scanning, it displays detailed information about the medication - name, dosage and potential side effects. It helps you quickly check basic information about the pills you find, increasing safety and confidence when taking the medication.

💊 ✨ MedScan
  • Developer

😎💧 AquaVibe

https://www.twine.net/signin

Track your wellness journey with AquaVibe, your all-in-one companion for mood, emotion, and hydration tracking 😊💦

The application allows users to set up to 3 daily reminders for consistent tracking and visualize their well-being with beautiful, interactive charts 📈

👨‍💻 Technology Used

  • SwiftUI
  • HealthKit
  • Charts
  • UserNotifications
  • WishKit
  • StoreKit2, RevenueCat
  • TelemetryDeck
  • AVKit, AVFoundation

🎥 AquaVibe ‘in action’

https://www.twine.net/signin

🏆 My standout success is…

AquaVibe wac created from scratch to fully working iOS Application, during RevenueCat Ship-a-ton competition. AquaVibe won Participation Prize during in RevenueCat Ship-a-ton competition:

https://www.twine.net/signin

The most challenging part was to understand ‘State of Mind’ logic.
From the documentation and sample project, was not so easy justified, so I needed to do a lot of tests to check and understand, how such function in ‘State of Mind’ logic works (for example, how correctly develop function to fetch and save mood or emotions data to Apple HealthKit).

Also, ‘State of Mind’ logic is something completely new, starting from iOS 18, so not so much information was available on the Internet.

✅ Entireness

Nevertheless, while creating this mood and water intake reminder app, I have also included the following:

  • Concurrency
  • Error handling & alerts
  • Text input validation
  • Project organization - MVVM Architecture
  • Published in App Store (09/2024)

ℹ️ License

The AquaVibe is the property of Marcin Jędrzejak. Unauthorized copying, distribution, or modification of this application is strictly prohibited.

®️ 2026 All rights reserved by Marcin Jędrzejak.

😎💧 AquaVibe
  • Developer

Education

Master of Arts in Management · Bydgoszcz University of Science and Technology - Management department2013 – 2015

Certifications and awards

SwiftUI Advanced Architecture2025

https://app.kajabi.com/certificates/d6f12f3e

iOS mobile application programming course in SWIFT: Advanced level2022

https://maartinj.notion.site/Swift-Academy-6ec2764d01b2450e8c46c3237805dcb7

Swift: LinkedIn Skill Evaluation Badge2021

https://maartinj.notion.site/Swift-LinkedIn-Skill-Evaluation-Badge-5bc10838044d4221ba42618ca726023d?pvs=4

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