Sergei Sedov, Developer in Belgrade, Serbia
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Sergei Sedov

Verified Expert  in Engineering

Software Developer

Belgrade, Serbia
Toptal Member Since
March 12, 2018

Sergei has over seven years of experience in iOS app development (Objective-C and Swift) and more than a decade in J2EE. He also possesses a bachelor's degree in computer science and, in his career, has successfully led and communicated with QA and product teams. Sergei joined Toptal to find long-term iOS projects where he can develop products from scratch—building architecture that allows refactoring and unit testing.


A Global Freelancing Platform
CallKit, Carthage, Viper, RealmSwift, Objective-C, Swift
Dashboard Systems
Fastlane, TeamCity, Delivery, Keychain, iOS, Security, AES, Encryption, Swift...
Core Location, MapKit, Code::Blocks, Multithreading, Core Data




Preferred Environment

Git, Xcode, Jira, Stash, GitHub, Miro

The most amazing... I've developed allowed clients and freelancers from all over the world to connect with each other.

Work Experience

Senior iOS Developer

2016 - 2018
A Global Freelancing Platform
  • Designed and developed this platform's application; this app is rated five stars in the App Store.
  • Built various features for the app including job search, submit proposal, messenger, and freelancer search features.
  • Implemented code reviews.
  • Interviewed candidates for team positions.
  • Participated in teaching sessions.
  • Supported the migration to internal modules architecture with the modified version of Carthage.
  • Worked with CallKit when implementing VoIP calls.
  • Communicated with several back-end teams.
  • Aided the development of the Reactive library (ReactiveCocoa and RxSwift analog).
Technologies: CallKit, Carthage, Viper, RealmSwift, Objective-C, Swift

iOS Team Lead

2013 - 2016
Dashboard Systems
  • Contributed to the development of almost all the application features including meetings, agenda items, decisions, tasks, message center, and notification center.
  • Implemented a Core Data-based custom server synchronization mechanism.
  • Worked with Core Security, iOS Keychain, OpenSSL, and custom data encryption and digital signature providers.
  • Led a team.
  • Participated in design discussions, sprint plannings and code reviews.
  • Supported the build of a custom iPad UI that allowed BoardMaps to win the RedDot design award in 2016.
  • Developed, with a team, a localization system with right-to-left languages support.
  • Constructed a custom calendar controller for iPad.
Technologies: Fastlane, TeamCity, Delivery, Keychain, iOS, Security, AES, Encryption, Swift, Objective-C, JSON, User Interface (UI), Core Data

iOS Developer

2012 - 2012
  • Developed an iOS application for
Technologies: Core Location, MapKit, Code::Blocks, Multithreading, Core Data

iOS Developer

2012 - 2012
  • Built a UI for VoIP calls.
  • Integrated it with the VoIP library.
  • Developed a UI for contact management.
Technologies: UIKit, Objective-C, Xcode

Senior J2EE Developer

2011 - 2012
  • Developed internal automation systems based on the SOA platform FLEXTERA (J2EE, Web Services).
  • Managed a group of developers and testers.
  • Implemented configuration management and release installations.
Technologies: Jakarta EE

Deputy Head of Unit

2010 - 2011
  • Developed iBank2 internet banking.
  • Planned and assigned tasks.
  • Reviewed code.
  • Built custom versions of the internet banking systems for the Bank of Moscow and Absolut Bank.
Technologies: Scrum, GlassFish, Apache Tomcat, Microsoft SQL Server, Oracle, PostgreSQL, ActiveMQ, DBUnit, JUnit, JSF

J2EE Developer

2008 - 2010
  • Maintained already existing modules for the publishing house, Geleos.
  • Designed and developed new modules for the publishing house, Geleos.
Technologies: Apache POI, MySQL, Hibernate, EJB 3, Tomahawk Music Player, RichFaces, JSF, Jakarta EE

A Global Freelancing Platform iOS Application

On this project, I designed and developed the entire application; including implementing code reviews and interviews with the candidates. I contributed to the development of certain features of the app including job search, submit proposal, messenger, and freelancer search features. I also taught and mentored other developers in training sessions and migrated the app to an internal module's architecture. In addition, I implemented VoIP calls and also communicated with several back-end teams.

Dashboard Systems | BoardMaps
For Dashboard Systems, I developed the enterprise iPad application BoardMaps.

Avtodor | iOS App

I developed this app from scratch using Objective-C, REST API, and Core Data as storage.

Plain Flashcards | iOS App
This was built with Swift, Core Data, and RxSwift.

Invisible City

I refactored and improved a small project for the European Union National Institutes for Culture. Specifically, I extracted all the business logic into separate components, implemented new search filters, and rewrote the interaction with the API.
2004 - 2009

Specialist's Diploma in System and Internet Programming

Moscow State University of Economics, Statistics, and Informatics - Moscow, Russia


RxSwift, AES, Apache POI, RichFaces, DBUnit


Git, Apple Push Notifications, IntelliJ IDEA, Code::Blocks, Tomahawk Music Player, CallKit, Apache Tomcat, ActiveMQ, Xcode, TeamCity, Fastlane, Photoshop 2018, Sketch, Zeplin, Jira, Stash, GitHub, Miro


RealmSwift, ReactiveCocoa, Core Data, Viper, Core Location, UIKit, Hibernate, JSF, JUnit, MapKit, Spring Boot


Swift, Objective-C, Java, SQL


VIPER Architecture, Agile, Scrum


Jakarta EE, Oracle, Keychain, AWS Elastic Beanstalk, Linux, iOS, MacOS


JSON, Microsoft SQL Server, Amazon S3 (AWS S3), PostgreSQL, MySQL


User Interface (UI), Encryption, Security, Delivery, Multithreading, OOP Designs, EJB 3, GlassFish, Carthage, Enterprise Java Beans (EJB)

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