Freelancer profile translated to English.
Back to original languageAbout Sébastien
Experienced iOS developer, I assist startups and companies in designing, developing, and optimizing high-performing, scalable, and product-oriented mobile applications.
Before specializing in iOS development, I worked in creative environments, which gave me an unusual UI/UX sensitivity for a developer.
Result: I don't just deliver working code, I deliver an experience that is felt. Fluidity, animations, visual consistency: these details are not optional in my work.
I am involved in the entire application lifecycle: architecture, development, refactoring, performance optimization, UX improvement, preparation for production.
Technical Expertise:
- Swift
- SwiftUI & UIKit
- Clean Architecture
- TDD & unit tests
- Performance optimization & memory management
- App Store deployment
My added value:
- Clean, maintainable, and documented code
- Long-term vision (scalability and controlled technical debt)
- Strong UI/UX sensitivity for fluid and modern interfaces
- Business impact and product quality oriented approach
Among my concrete results: 62% reduction in crashes on a consumer application (crash-free users > 99%), two-thirds reduction in memory footprint, complete refactoring of network layers on apps with millions of users.
What you get by working with me:clean, maintainable, and scalable code, a performant and stable application, and real attention to the final user experience.
🚀 Do you have an iOS project to launch, stabilize, or evolve?
Let's talk about it!
French
Native or bilingual
English
Fluent
Thai
Basic
German
Basic
Can work on-site
Paris (up to 50km)
Experience
- ElokenceiOS DeveloperSOFTWARE PUBLISHINGNovember 2023 - October 2025 (1 year and 11 months)Chartres, FranceAs part of the Scrum team, I am responsible for the iOS development of Pépitch, a movie and TV series recommendation app based on artificial intelligence. I have led major improvements to enhance stability and performance, and enrich the user experience.
- Complete refactoring of the network layer with an automatic retry mechanism for failed calls.
- Expansion of features for the account-less mode, increasing engagement of new users.
- Implementation of tutorials to improve onboarding and retention. Added TV series, enriching the content catalog.
- Development of 3 new user experiences, modernizing the interface and interaction.
- Implementation of authentication with Apple and Google, simplifying user access.
- Development of a social section allowing user following, fostering interaction.
I also worked on Akinator, a virtual genie that guesses who or what the user is thinking of, using an advanced AI-based algorithm. Available on iOS and Android, it attracts millions of players worldwide.Tasked with modernizing and optimizing the iOS application, I led a strategic technical overhaul aimed at improving network resilience and user experience.- Complete refactoring of the network layer in Swift, with an automatic retry mechanism for failed calls, improving user experience in case of poor connection or server issues.
- The new network layer was designed to be usable on both parts of the app coded in Swift and on older parts coded in Objective-C.
- Creation of a new splash screen and grouping of network calls necessary for app initialization
- Display of a generic, multilingual popup informing the user of the encountered network issue, allowing them to retry their action.
- paris promeneursDevelopment of the MVP / v1 of the Paris-Promeneurs application.TRAVEL AND TOURISMJune 2022 - December 2022 (7 months)Paris, FranceFor the Paris-Promeneurs website, specializing in guided tours in Paris and its surroundings, I am responsible for developing, from scratch, a first version of the mobile application, which will be the iOS adaptation of the existing site.The mission was divided into two parts, first defining the specifications, technical and functional requirements.Leveraging my design experience, I first created the UX design for the future application.Once the visual choices were approved by the client, I developed the application.It will be structured around four areas:- As Paris-Promeneurs is also a content website on Parisian heritage and architecture, there will be a "Featured" section displaying the latest articles.- The "Tours" section will allow users to book a guided tour.- The "Search" section will display search results corresponding to the terms the user has entered in the provided field.- The application will also allow the user to view points of interest around them in two ways:-> Use a map that displays points of interest around them, marked by different icons depending on the category.-> Use augmented reality to view points of interest around them in real time. Upon launch of the application on the Appstore, this last feature will only be available for premium users.- Finally, the application will include a settings menu, a way to view reservations, etc.The application was built with MVVM architecture, using UIKit and various associated frameworks: MapKit, external libraries via CocoaPods (Alamofire, etc.).
- TracotooiOS DeveloperTRANSPORTATIONJanuary 2023 - June 2023 (5 months)Paris, FranceAvailable on the Appstore:https://apple.co/3qQElAtFor the Tracotoo application, a carbon footprint tracking app, I designed the user interfaces with Figma, and the visual identity of the application: logos, font choices, animations, creation of icons and images.After completing the graphic design phase, I coded the application in native Swift, mainly with the UIKit graphical framework. I also created the backend with Firebase Firestore for the database, and Firebase Auth for authentication.Users of the application will be able to use it without an account, and save data on their phone via CoreData, or save it to the cloud via Firebase.The application is structured around 3 main features:- Management of their vehicle fleetThe user can register up to 10 vehicles, choosing from a list of manufacturers and models.- Carbon footprint calculation:By entering the start and end addresses of a trip, the application will automatically calculate the trip distance along the most common route. The user can then see the carbon footprint of the trip, refined based on the vehicle being used.- Carbon footprint counter:The application displays an annual and monthly count of the user's carbon footprint.Through the menu, the user can also access their account management.
Reviews
Franck
paris promeneurs
Reviewed on 1/12/2023
Sébastien is serious, reliable, and very competent. A very valuable quality, he was proactive with suggestions for the interfaces and met deadlines. I recommend him!
A
Arnaud
Elokence
Reviewed on 5/2/2024
Recommendations
These freelancer profiles also match your criteria
Agatha Frydrych
Backend Java Software Engineer
4.7
(3)
2
Baptiste Duhen
Fullstack developer
4.6
(4)
5
Amed Hamou
Senior Lead Developer
4
(2)
7
Audrey Champion
Web developer
4.3
(3)
4
Education
- Application Developer - iOSOpenClassrooms2022- Concevoir l’architecture technique de l’application, - Créer son interface et ses éventuelles animations, gérer l’interaction avec l’utilisateur. - Analyser les besoins à partir du cahier des charges défini par les clients ou les chefs de projet, - Définir les différentes étapes de fonctionnement de l’application, - Développer, tester et valider les fonctionnalités de l’application, - Assurer le support technique de l’application et de produire une documentation technique et fonctionnelle - Apporter des corrections de bugs et d’effectuer des mises à jour.
Certifications
- Create a web service in Swift with Vapor 4Purple Giraffe2022
- Add lists to your iOS applicationsOpenClassrooms2021