Prakash Kumar Kotwal, Developer in Berlin, Germany
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Prakash Kumar Kotwal

Verified Expert  in Engineering

iOS Developer

Berlin, Germany
Toptal Member Since
September 7, 2022

Prakash is an experienced, analytical, and results-driven iOS engineer with over 10 years of professional experience in the industry. He is passionate about mobile technologies, building, scaling, and delivering technical solutions that bring value to users. He loves working in dynamic and challenging environments and is experienced in all stages of the development process. Prakash can lead and coordinate teams and contribute to the team with hands-on work.


Payrix - WorldPay - FIS
Android, iOS, iOS SDK, iPhone SDK, Swift 3, Swift 4, Swift 5, CocoaPods...
iOS, Swift 1, Swift 3, Swift 4, Swift 5, Objective-C, iOS SDK, SDKs, SwiftUI...
Portal Labs, Inc.
Swift, SDKs, SDK Development, Software Development Toolkits (SDK), Kotlin, Web3...




Preferred Environment

Swift 5, Objective-C, Swift 2, Swift 3, iOS, Swift 4, iOS Camera, Google Maps SDK, Firebase iOS SDK, Offline Maps

The most amazing...

...thing I've developed is a video editing app called StoryMedia, which uses an in-depth implementation of the AVFoundation framework.

Work Experience

Lead iOS Developer

2021 - PRESENT
Payrix - WorldPay - FIS
  • Worked as a senior iOS developer at Payrix, focusing on the complex iOS SDK and payment-related functionalities.
  • Developed and maintained the iOS SDK at Payrix. Handled payment-related operations and integrations with BBPOS devices for card present solutions.
  • Played a key role in the EMV migration project, ensuring compliance and a smooth transition of payment processes.
  • Expanded expertise to include Android development with Java, specifically working on Pax and Verifone devices for semi-integrated payment solutions.
  • Developed proficiency in the Swift programming language, enabling efficient code development and maintenance of iOS applications.
Technologies: Android, iOS, iOS SDK, iPhone SDK, Swift 3, Swift 4, Swift 5, CocoaPods, Core Data, iOS Frameworks, SDK Development

Lead iOS Developer

2015 - PRESENT
  • Started as a freelance iOS developer and later worked as a full-time employee on the app development side.
  • Added multiple features, including a payment gateway, animations, and some cloud-based chat features using Firebase.
  • Updated the code from Objective-C to Swift and continually updated the code to the latest Swift syntax.
  • Managed a team of five developers working on Android, the back end, and iOS to add and update features in the app.
Technologies: iOS, Swift 1, Swift 3, Swift 4, Swift 5, Objective-C, iOS SDK, SDKs, SwiftUI, CocoaPods, Core Data, Core ML, Firebase, Firebase iOS SDK, APIs, Minimum Viable Product (MVP)

Swift/Kotlin SDK Developer

2024 - 2024
Portal Labs, Inc.
  • Developed comprehensive unit tests to verify the functionality and stability of key classes, enhancing code reliability.
  • Implemented updated Swift formatting rules in the project's GitHub repository to maintain code consistency and readability.
  • Participated actively in team meetings and code reviews, providing feedback and suggestions for process improvements.
  • Wrote GitHub Actions to automate various development tasks and workflows.
Technologies: Swift, SDKs, SDK Development, Software Development Toolkits (SDK), Kotlin, Web3, Xcode, Android, Android Studio, Git, GitHub Actions

Freelance iOS Developer

2020 - 2021
Kantipur Publications Pvt
  • Developed the complete app for e-Kantipur, used by millions of people in and out of Nepal, including the US, the UK, Australia, and the Gulf countries.
  • Updated the Objective-C code to Swift versions 2 and 3.
  • Developed iOS apps for e-Kantipur, as well as other news apps for Kantipur. They can be viewed through this link:
  • Developed various apps for Kantipur. The apps can be viewed through these links: and
Technologies: Swift 2, Objective-C, Custom Keyboards, Core Data

Senior iOS Developer

2018 - 2019
Info Tmt
  • Contributed to some projects that included an IoT feature for major European brands.
  • Added a chat feature to a US-based dating app and updated the code to the latest Swift syntax.
  • Worked directly under the CEO to manage the Jira dashboard.
Technologies: iOS, Swift, Core Data, Objective-C, APIs, Minimum Viable Product (MVP)

Senior iOS Developer

2014 - 2018
Grafi Offshore Nepal Pvt
  • Updated some of the app's code from Objective-C to Swift.
  • Contributed to developing a small animation game on SpriteKit, including some of the app's creative animations.
  • Collaborated in developing enterprise edition apps to train their employees on their brand for multiple clients from Europe.
Technologies: iOS, Objective-C, Swift, Swift 1, Swift 2, Swift 3, Core Data, Firebase, Firebase iOS SDK

iOS Developer

2012 - 2014
E-Signature Pvt
  • Started as a junior iOS developer and updated my skills to lead a team of four developers.
  • Contributed to numerous projects, which included features like map or custom map integration and chat and custom camera implementation.
  • Handled over 15 projects from beginning to submission on the App Store.
Technologies: iOS, Objective-C, Core Data

GEM | A Social Media Marketing App
An app written in Swift that meets 98% of the designer's expectations on UI. I coded on iOS and helped the back-end developer create the API structure. I also distributed tasks among the team to work and complete on time.

StoryMedia | A Video Editing App

A video editing app that allows users to create videos from still images or recorded videos, merge multiple photos and videos, and add or update music. As an iOS developer, I added code to support multiple soundtracks on a single video and enable merging multiple photos and videos. I also added code to allow audio track volume dipping at the end of a first video and the start of a second video, and so on.

Regulur | A Services Booking App

An iOS-based app that works to schedule appointments for haircuts and salon services. As an iOS engineer, I started the code, updated the UI, and integrated back-end services with the payment deployment.

Navigate Offline | An Offline Map

An app that allows users to download maps for navigation without using cellular data. As an iOS developer, I integrated the offline map bundle on the app and added all the codes to navigate maps, add routes, and manage settings.

Travelbook | A Travel-sharing Community App
An RxSwift-based app for travelers to share their stories, including photos and short videos. As an iOS developer, I updated their RxSwift code to the latest syntax. I also upgraded some of the old codebases to the latest Swift syntax.

Klom – WorkOS

An iOS-exclusive app built on SwiftUI that revolutionizes job seeking and hiring. Job seekers can apply for positions using video submissions, adding depth to their applications. Videos allow applicants to showcase skills, personality, and enthusiasm, giving employers a comprehensive view of their fit for the job.

On the other hand, employers can review video pitches submitted by candidates, gaining deeper insights into qualifications and demeanor. This approach streamlines recruitment and fosters interactive connections.

The app doesn't stop at traditional jobs; it extends to gig work. Job seekers can create and promote gigs through video pitches, offering versatility in their work offerings. Employers can easily browse these pitches and book services.

In summary, this SwiftUI-based iOS app transforms the job market with dynamic video communication. It empowers job seekers and providers with an efficient, engaging platform, facilitating seamless connections and fostering growth and success.
2008 - 2012

Bachelor of Technology Degree in Computer Science

Lovely Professional University - Phagwara, Punjab, India


iOS Native Libraries, REST APIs, Codable, Google Maps, Alamofire, CocoaPods, iOS API, Parse SDK, Stripe, Stripe API, Core Animation, Core Image, RxSwift, PayPal API, MapKit API, Google Maps SDK, Firebase iOS SDK, Mapbox iOS SDK, WebRTC, Xamarin.iOS


Xcode, TestFlight, GitHub, Firebase Authentication, Braintree SDK, Git, AVPlayer, Moya, Android Studio


UIKit, Cocoa Touch, iOS SDK, Core Data, Core Bluetooth, Viper, iOS Frameworks, MapKit, SwiftUI, ARKit, RealmSwift, iOS SceneKit, Multipeer Connectivity, Core ML, Metal, iPhone SDK


Swift 5, Swift, Swift 1, Swift 2, Swift 3, Swift 4, Objective-C, XML, Java, Kotlin


Mobile Development, REST, Model View ViewModel (MVVM), Test-driven Development (TDD), Unit Testing, VIPER Architecture


iOS, Mobile, Apple, Parse, Bluetooth Low Energy (LE), Firebase, Xamarin, Mapbox, Android, WatchOS, Apple Watch, Apple TV, tvOS


JSON, Realm


Mobile Apps, Mobile App Development, App Store, iPad, APIs, API Integration, Geolocation, Payment APIs, Cost Estimation, iPadOS, Agile Practices, Technical Leadership, Minimum Viable Product (MVP), AVFoundation, User Interface (UI), iOS Camera, Bluetooth, Video Editing, BrainTree, Maps, OpenStreetMap, Image Manipulation, Video Codecs, Social Networks, SDKs, UI Testing, AR Interfaces, Location Services, Location Services and Maps, GPS, Mobile Architecture, Apple Pay, Internet of Things (IoT), UI Frameworks, Custom Keyboards, PayPal, Point of Sale, SDK Development, Software Development Toolkits (SDK), iOS Video, Offline Maps, User Experience (UX), Augmented Reality (AR), Mapbox SDK, WiFi Direct, Architecture, Accessibility, Bluetooth Beacons, WatchOS UI, iMessage, Near-field Communication (NFC), Google Play Store, Over-the-top Content (OTT), iOS TV, iPhone, TV, Networks, Web3, GitHub Actions

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