Mobile Software Engineer · iOS & Android

Native apps for iOS and Android, built end to end.

I'm Kerem. For six years I've shipped mobile software — from the modular framework behind white-label retail apps at Pensa Systems to my own products, written natively for iPhone, Android, Apple Watch and Wear OS.

See the work Get in touch LinkedIn

Now: Engineer at Pensa Systems
Shipping: ProgressCam 1.3 · Still 1.4
Based: Istanbul, Turkey

Selected work

Products I design, build and ship myself.

Each one is a full product — native apps on both platforms, a shared backend, subscriptions, localization, store listings and a website — owned from first commit to release.

ProgressCam iOS 1.3 · Android 1.0

Progress photos that actually line up.

A progress camera. A ghost overlay of your last shot guides the next one, then on-device landmark detection aligns every photo — so a before-and-after shows the change, not the camera angle. Compare, then export as a timelapse, GIF or collage.

progresscam.app

The same room before the remodel, stripped to the studs

Drag to compare. Two demo photos taken weeks apart, aligned by ProgressCam.

01 One alignment engine, two platforms
Vision on iOS; ML Kit, MediaPipe and OpenCV on Android. The alignment math is identical on both, verified against golden vectors generated from the iOS source.
02 A shared backend, no conversion layer
Both apps speak to the same Firebase project and RevenueCat entitlements, so a project started on iPhone restores on Android with the same sign-in.
03 An on-device media pipeline
Timelapse video, animated GIF, slideshow and collage exports, with downsampled decodes and tiled rendering to stay inside mobile memory limits.
04 Tested and accessible
More than 2,400 unit tests on Android alone. Built for VoiceOver, TalkBack and the largest text sizes, in four languages.

Camera screen with a translucent ghost of the previous photo over the live preview — Ghost overlay camera iOS

Compare screen on iPhone with a slider between two aligned portraits — Compare, aligned iOS

The same Compare screen on Android, in Material 3 — The same screen, native Android

iOS: Swift · UIKit · SwiftData · Vision · AVFoundation · Coordinators + MVVM
Android: Kotlin · Jetpack Compose · Room · Hilt · CameraX · ML Kit · MediaPipe · OpenCV
Shared: Firebase Auth, Firestore, Storage & App Check · RevenueCat · static site on Cloudflare

In 4 · hold 4 · out 4 · hold 4

Still iOS 1.4 · Android 1.4 · watchOS · Wear OS

A calm moment, on your phone or your wrist.

A private stress companion. Log a stressful moment in one tap, breathe through a guided technique, and see when and where stress peaks. No account, no ads — your notes and health data stay yours.

Website

Still's Insights screen on iPhone — iPhone

Still's Insights screen on Android — Android

A breathing session on Apple Watch — Apple Watch

Still's home screen on a round Wear OS watch — Wear OS

01 Four form factors, one feature set
iPhone, Android, Apple Watch and Wear OS at feature parity — the same techniques, insights and achievements, backed by 840+ unit tests.
02 Heart-rate aware
With HealthKit or Health Connect, Still spots a spike above your baseline and offers a breathing session straight from the notification.
03 Lives on the system surface
Home screen widgets, watch complications, a Wear OS tile, Control Center, Quick Settings and Siri Shortcuts — calm without opening the app.

iOS & watchOS: Swift · UIKit · SwiftUI · Core Data + CloudKit · HealthKit · WidgetKit · App Intents
Android & Wear OS: Kotlin · Jetpack Compose · Compose for Wear OS · Room · Hilt · Health Connect · Glance
Shared: Firebase Remote Config & Crashlytics · RevenueCat · English, Turkish, French, Spanish

Songstamp iOS

A daily music journal — one song a day to capture a mood, with a social feed and Apple Music playlists. SwiftUI, SwiftData, MusicKit and Firebase.

App Store ↗ Website ↗

Toolkit

Two native stacks, held to one standard.

I don't reach for a cross-platform layer. I build each app in its platform's own idiom, and keep the two in step through shared logic, shared backends and tests.

iOSAndroid

LanguageSwift, Objective-CKotlin

UIUIKit, SwiftUIJetpack Compose, Material 3

DataSwiftData, Core Data, CloudKitRoom, DataStore

Camera & mediaAVFoundation, ImageIOCameraX, Media3

On-device MLCore ML, Vision, PyTorch LiteML Kit, MediaPipe, OpenCV

HealthHealthKitHealth Connect, Health Services

System surfacesWidgetKit, App IntentsGlance, tiles, app shortcuts

WearableswatchOS, WatchConnectivityWear OS, Data Layer

ArchitectureCoordinators, MVVM, SPM modulesHilt, MVVM, Gradle modules

DeliveryXcode Cloud, TestFlight, App StoreGradle, R8, Google Play

On both FirebaseRevenueCatLocalizationAccessibilityUnit testing

On-device ML

Moving cloud-trained recognition models onto the phone with Core ML and PyTorch Lite — including a Swift Package I built to bring PyTorch Lite and TorchVision Ops to iOS.

Modular architecture

Turning a monolith into a configurable framework that ships several white-label apps from one codebase, and working inside one that powers 2,000+.

Beyond the client

Firebase rules, functions and sync; TypeScript and Node.js backends; a Unity title led end to end. Comfortable wherever the product needs me.

Experience

Six years of shipping, three companies.

Retail computer vision, social apps and games, and a news platform behind thousands of apps.

Sep 2024 — Present
Current

Pensa Systems

Software Engineer, iOS & Android · Austin, TX (remote)

Rebuilt the iOS app from a SwiftUI monolith into PensaCore, a modular UIKit framework that now powers multiple white-label and partner-specific retail apps.
Designed and built Pensa ODR, moving the company's recognition models from the cloud to Core ML — near-cloud accuracy with no network dependency.
Wrote a Swift Package from scratch that combines PyTorch Lite and TorchVision Ops, so cloud-trained models deploy straight to the device.
Extended the work to Android in Kotlin, shipping features and porting the ODR on-device inference pipeline to parity with iOS.
Built Pensa Actions, which turns shelf scans into a prioritized task list so reps fix out-of-stocks in the aisle.

Oct 2023 — Sep 2024

Sociable

Software Engineer, iOS & Backend · Istanbul

Engineered a full in-app wallet so creators can receive and manage revenue.
Designed and built Bubbles for Hola, and resolved critical latency issues in four-player Rummikub.

Aug 2022 — Oct 2023

Visiolink

Software Engineer, iOS & Backend · Aarhus, Denmark (remote)

Worked on the modular iOS architecture behind 2,000+ news apps, delivering ePaper apps for Amedia, Irish Times, De Persgroep and BILD.
Built configuration tools that update live apps in real time, and moved legacy Objective-C modules to Swift.

Jun 2020 — Aug 2022

Sociable

Software Engineer, iOS, Backend & Unity · Istanbul

Led end-to-end development of Word Game, the company's first Unity title.
Migrated the codebase from Objective-C to Swift 5 and re-implemented the backend in type-safe TypeScript.

2022

Boğaziçi University

B.Sc. in Computer Engineering · Istanbul

Thesis: an iOS app for real-time food recognition and nutrition lookup with Core ML.