Zhifu is available for hire
Hire ZhifuZhifu Ge
Verified Expert in Engineering
Swift Developer
Waterloo, ON, Canada
Toptal member since September 17, 2018
Bio
Zhifu is a native iOS developer with four years of experience and six apps that are live in the App Store. Fluent in both Swift and Objective-C, he writes clean, maintainable, scalable, and fast code. Zhifu has extensive experience working in agile teams of all sizes and communicates exceptionally well with teammates and QA staff.
Portfolio
Dubsmash
RxCocoa, RxSwift, Swift, iOS
Reddit, Inc.
Swift, iOS App Development, Xcode, SwiftUI, UIKit, Core Data, AVFoundation...
Brierwood Design Co-operative
Swift, Objective-C, iOS
Experience
- Swift - 4 years
- Objective-C - 4 years
- UIKit - 4 years
- REST APIs - 4 years
- Git - 4 years
- RxSwift - 3 years
- Core Bluetooth - 1 year
- Cloud Firestore - 1 year
Preferred Environment
Git, Xcode, MacOS
The most amazing...
...piece of code I've written is a container view controller that performs and looks great on smaller screens on iPhones and bigger screens on iPads.
Work Experience
iOS Engineer
2018 - PRESENT
Dubsmash
- Developed major new features for a large-scale social media app that has over 1 billion monthly video views.
- Led the team on implementing several major architecture design patterns to make the code base more maintainable, testable, and scalable.
- Collaborated with the product team releasing a new version every two weeks since the start date.
Technologies: RxCocoa, RxSwift, Swift, iOS
Senior iOS Engineer
2021 - 2022
Reddit, Inc.
- Authored the on-app video creation SDK for the official Reddit app on iOS, which became the foundation of the native video post-creation process of the Reddit app.
- Improved video playback performance drastically on the official Reddit app on iOS.
- Migrated the majority of the post-creation code from Objective-C to Swift.
Technologies: Swift, iOS App Development, Xcode, SwiftUI, UIKit, Core Data, AVFoundation, GraphQL
iOS Developer
2016 - 2018
Brierwood Design Co-operative
- Built a continuous integration system using Fastlane, Jenkins, Bash, and Ruby, for an enterprise-grade iOS app that has several "white label" flavors, some of which uses clients' own signing credentials.
- Converted approximately 30% of a 20,000-line Objective-C code base to Swift 3, and greatly improved the code quality along the way.
- Implemented the tags view and map view of an enterprise iOS app. These two features became the "killer feature" of two major releases.
- Led the effort of formally establishing the team's Swift coding standard and style guidelines.
- Designed, implemented, and released an iOS app as a one-person team, greatly reduced the stress of a very understaffed firm.
- Started and led the company's "Lunch and Learn" program, a weekly session for the team to learn the latest in Swift and iOS development.
- Worked on a tvOS app using RxSwift and RxCocoa, and organized 2 training sessions on Rx and functional programming.
Technologies: Swift, Objective-C, iOS
Software Developer
2016 - 2016
Wind River Systems
- Developed a Python application for internal OS testing that connects to hundreds of targets, and executes tests on them.
- Implemented the conditional execution part of a domain-specific programming language using Python. It was the killer feature of a very successful major release.
- Implemented the GOTO keyword of a domain specific programming language.
Technologies: C, JavaScript, Python
Experience
Dubsmash iOS App
Dubsmash is the second-largest short-video social media app in the US, with over 1 billion video views per month. Zhifu has been the principal developer of the iOS app since October 2018, contributing 500+ commits.
- Owned 30+ bi-weekly releases
- Owns several vital areas of this large-scale social media app: the feed, the camera,
and the direct messages
- Leads the team on implementing several architecture design patterns to make the
codebase more maintainable, testable, and scalable: Dependency Injection, The Coordinator Pattern, and MVVM
- Owned 30+ bi-weekly releases
- Owns several vital areas of this large-scale social media app: the feed, the camera,
and the direct messages
- Leads the team on implementing several architecture design patterns to make the
codebase more maintainable, testable, and scalable: Dependency Injection, The Coordinator Pattern, and MVVM
ProntoForms
https://itunes.apple.com/app/prontoforms-mobile-forms/id305587992ProntoForms is the iOS client of ProntoForms Corporation’s mobile forms system. It presents custom-made forms fetched from the server, let the users fill in data, and send the data back to the server.
ProntoForms has been a successful solution trusted by large companies like Unilever, AT&T, TOSHIBA, and BP.
I worked on ProntoForm during my employment with Brierwood Design Co-operative, from November 2016 to February 2018.
Technologies:
UIKit, Grand Central Dispatch, Core Data, MapKit, AVFoundation. Core Graphics, Core Animation, Amazon AWS, Rest APIs, Objective-C, Swift, Fastlane.
ProntoForms has been a successful solution trusted by large companies like Unilever, AT&T, TOSHIBA, and BP.
I worked on ProntoForm during my employment with Brierwood Design Co-operative, from November 2016 to February 2018.
Technologies:
UIKit, Grand Central Dispatch, Core Data, MapKit, AVFoundation. Core Graphics, Core Animation, Amazon AWS, Rest APIs, Objective-C, Swift, Fastlane.
Wave Whiz
Wave Whiz is an iOS app for maximal overlap discrete wavelet transform (MODWT) analysis. It loads signal data from text files, or from the console where a user can type or paste in the values. Its main features include multi-resolution analysis (MRA), multi-scale analysis of variance (ANOVA), and denoising. Analysis results can be exported to text files.
Wave Whiz is heavy on data processing. To make the UI sleek and always responsive, I took full advantage of Grand Central Dispatch, NSOperations, and multi-threading best practices. The result is a stable, high performance, and power-efficient app that has been very well received by the client and the client's users.
Technology:
UIKit, Grand Central Dispatch, Accelerate (Apple's high-performance, energy-efficient vector-processing framework), vDSP (Apple's digital signal processing framework). Swift, C, Fastlane.
Wave Whiz is heavy on data processing. To make the UI sleek and always responsive, I took full advantage of Grand Central Dispatch, NSOperations, and multi-threading best practices. The result is a stable, high performance, and power-efficient app that has been very well received by the client and the client's users.
Technology:
UIKit, Grand Central Dispatch, Accelerate (Apple's high-performance, energy-efficient vector-processing framework), vDSP (Apple's digital signal processing framework). Swift, C, Fastlane.
ECG Wiz
ECG Wiz is an iOS app for high-frequency ECG waveform analysis.
The app has a very complex 7-stage data processing system. To make the user interface always responsive, preserve battery life, and increase the processing speed, I optimized every aspect of the architecture and algorithm design, to the extent that re-implementing certain functions in C instead of Swift. The payoff is huge. It runs super fast, comparable to desktop-class applications of similar functions.
Technology:
UIKit, Grand Central Dispatch, Accelerate (Apple's high-performance, energy-efficient vector-processing framework), vDSP (Apple's digital signal processing framework). Swift, C, Fastlane.
The app has a very complex 7-stage data processing system. To make the user interface always responsive, preserve battery life, and increase the processing speed, I optimized every aspect of the architecture and algorithm design, to the extent that re-implementing certain functions in C instead of Swift. The payoff is huge. It runs super fast, comparable to desktop-class applications of similar functions.
Technology:
UIKit, Grand Central Dispatch, Accelerate (Apple's high-performance, energy-efficient vector-processing framework), vDSP (Apple's digital signal processing framework). Swift, C, Fastlane.
The Official Reddit App on iOS
https://apps.apple.com/us/app/reddit/id1064216828A social media app for one of the most popular platforms in the world, enjoyed by hundreds of millions of users worldwide. I was the original author of the video creation SDK used in the app's post-creation process. I also made significant contributions to the overall post-creation process.
Education
2014 - 2016
College Diploma in Computer Programming
Algonquin College - Ottawa, Ontario, Canada
Skills
Libraries/APIs
RxSwift, RxCocoa, REST APIs, Firebase iOS SDK, Core Graphics, Core Animation
Tools
Xcode, Grand Central Dispatch, Git, Fastlane, Firebase Authentication, Firebase Analytics
Languages
Swift, Objective-C, C, GraphQL, Java, Ruby, Python, JavaScript
Frameworks
UIKit, Core Data, MapKit, Core Location, Core Bluetooth, Core ML, SwiftUI
Platforms
iOS, MacOS, Linux, Amazon Web Services (AWS)
Paradigms
Agile Software Development, Functional Programming
Storage
NoSQL, Cloud Firestore
Other
Firebase Hosting, AVFoundation, Data Encryption, Machine Learning, Firebase Cloud Functions, iOS App Development
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