Vilner Leonid — Senior iOS Developer

Expertise in iOS (6.5 yr.), Mobile Apps (6.5 yr.).

Last verified on January, 2026

Core Skills

Swift

6 yr.

UIKit

6 yr.

RxSwift

Combine framework

Crashlytics

Bio Summary

Senior iOS Developer with over six years of experience in developing high-performance mobile applications. Expertise in designing scalable architectures such as VIPER, MVVM, and Redux and in optimizing app performance through in-depth profiling and code refactoring. Proven track record of improving messaging app stability by 20%, reducing memory usage by 30%, and enhancing fin-tech app user interfaces with custom UI components and animations. Delivered an innovative Bluetooth mobile app, enhancing building time by 25% and memory usage by 15%. Proficient in Swift, UIKit, RxSwift, Combine, Firebase, and Mapbox, with the ability to collaborate seamlessly with cross-functional teams. Possesses an advanced level in English and a strong grasp of various development frameworks and tools.

Technical Skills

Programming Languages	Objective-C, Swift
Ruby Libraries and Tools	active admin
Mobile Frameworks and Libraries	Crashlytics, KeychainSwift, Lottie, Moya, RxSwift
JavaScript Frameworks	Lodash
JavaScript Libraries and Tools	Redux-Saga
Databases & Management Systems / ORM	Realm
UI Frameworks, Libraries, and Browsers	Auto Layouts (Figma), Chrome Extensions
Amazon Web Services	AWS ElastiCache, AWS Secrets Manager
UI/UX/Wireframing	Adobe Photoshop, Figma
iOS Libraries and Tools	Alamofire, CocoaPods, Combine framework, Core Audio, Core Bluetooth, Core Data, Core Foundation, Core Graphics, Core Location, MapKit, SceneKit, SnapKit, SwiftPM, SwiftUI, Swinject, UIKit, URLSession, Viper
Methodologies, Paradigms and Patterns	Clean Architecture, MVVM
Platforms	Fastlane
Mail / Network Protocols / Data transfer	GRPC
Third Party Tools / IDEs / SDK / Services	QMake
Other Technical Skills	Concurrency, Dispatch, English, Instruments, Kingfisher, MetalKit, NSOperation, WidgetKit

Work Experience

Senior iOS Developer, Bluetooth device mobile app

Duration: March 2019 - October 2020 (1 year 8 months)
Summary:

Developed an innovative mobile app for a Bluetooth device, focused on collaboration with hardware engineers and Android developers for Altos Inc
The project involved key feature implementation and code refactoring to improve building time and reduce memory usage while managing multi-threading for smooth app functionality

Responsibilities: Refactoring code modules, implementing key features, managing multi-threading
Technologies: Swift, UIKit, Multithreading (Grand Central Dispatch, Swift Concurrency, NSOperation)
Senior iOS Developer, High-performance messaging app

Duration: October 2020 - May 2023 (2 years 8 months)
Summary:

Delivered a high-performance messaging app with advanced chat features at Escape-Tech Ltd
The project entailed improvement of app stability, refactoring of legacy code for scalability, and optimization of app architecture

Responsibilities: Delivering a high-performance messaging app, improving app stability, refactoring legacy code, optimizing architecture for scalability
Technologies: Swift, UIKit, Xcode Instruments, Network profiling
Senior iOS Developer, High-load fintech apps for BCS Bank

Duration: June 2023 - Until now (2 year 5 months ongoing)
Summary:

Engaged in development of high-load fintech apps for BCS Bank at Umbrella Ltd
, playing a crucial role in ensuring secure operations, enhancing performance, UI latency, and efficiency while also working on feature parity across platforms and integrating Mapbox & CoreLocation to augment engagement

Responsibilities: Developing high-load fintech apps, improving performance through Redux architecture, enhancing UI latency, collaborating across teams, implementing features with Mapbox & CoreLocation, reducing memory usage, designing custom animations, leveraging CI/CD pipelines, conducting code reviews, leading performance optimization
Technologies: Swift, UIKit, Redux architecture, Mapbox, CoreLocation, custom UI components, CI/CD pipelines, performance profiling tools

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