Paul is available for hire
Hire PaulPaul Vasile
Verified Expert in Engineering
Mobile Developer
Bucharest, Romania
Toptal member since October 17, 2022
Bio
Paul is a senior software engineer specializing in iOS with 9+ years of experience building secure, scalable mobile applications for startups, fintech, and enterprise organizations. He combines expertise in software architecture, application security, AI-powered applications, and modern Apple technologies to deliver high-quality solutions to complex engineering challenges.
Portfolio
Marks and Spencer
iOS, SwiftUI, Swift, APIs, Mobile Development, Mobile App Development...
Salt Bank
Swift, SwiftUI, Mobile App Security, Native Mobile Apps, APIs...
Relatent Inc
SwiftUI, iOS, Software Architecture, APIs, Swift, Mobile Development...
Experience
- Mobile Development - 9 years
- APIs - 9 years
- Swift - 9 years
- iOS - 9 years
- SwiftUI - 9 years
- CI/CD Pipelines - 6 years
- Software Architecture - 6 years
- Supabase - 3 years
Preferred Environment
Slack, Jira, Git, Zoom, Webex, Teams, Confluence
The most amazing...
...thing I built was the refactored and modernized M&S shopping basket, improving scalability and maintainability for a feature used by millions of customers.
Work Experience
Senior iOS Engineer
2025 - PRESENT
Marks and Spencer
- Built production-grade iOS UI components adhering to accessibility standards (VoiceOver, Dynamic Type), improving usability across diverse user groups.
- Optimized app performance by profiling and reducing UI rendering bottlenecks, improving screen load times.
- Wrote unit and UI tests to improve code coverage and reduce regression issues during releases.
- Integrated GraphQL APIs and handled asynchronous data flows, ensuring reliable and responsive user experiences.
Technologies: iOS, SwiftUI, Swift, APIs, Mobile Development, Mobile App Development, Confluence
Mobile Security Engineer
2025 - 2025
Salt Bank
- Implemented robust security measures for App Store and Google Play builds, including runtime application self-protection, jailbreak and root detection, and camera injection safeguards.
- Performed comprehensive source code reviews to identify and mitigate potential security vulnerabilities within the application.
- Executed MASVS-compliant penetration testing on the mobile application to systematically identify security vulnerabilities, potential exploit vectors, and weaknesses.
Technologies: Swift, SwiftUI, Mobile App Security, Native Mobile Apps, APIs, Mobile Development, Mobile App Development, Confluence
Senior SwiftUI Developer
2025 - 2025
Relatent Inc
- Implemented caching mechanisms that optimized launch time by more than 50%.
- Integrated the iOS App with multiple API endpoints and ensured a safe, no-downtime approach when sunsetting old services.
- Created production-ready SwiftUI components according to the Figma design and integrated them into the existing production build.
Technologies: SwiftUI, iOS, Software Architecture, APIs, Swift, Mobile Development, Minimum Viable Product (MVP), Mobile App Development
Mobile and Back-end Lead Developer
2024 - 2025
LCI Traders & Developers LLP
- Created the MVP for the business based on existing designs and the product idea.
- Contributed to shaping the business model and feature prioritization.
- Delivered the mobile product and the back-end infrastructure in time for the scheduled release.
- Assisted with user acquisition, retention, and feedback collection.
Technologies: iOS, Swift, SwiftUI, Version Control, UIKit, Core Data, Testing, UI Testing, Multithreading, SDKs, Firebase, REST APIs, Amazon Web Services (AWS), PostgreSQL, Software Architecture, APIs, Mobile Development, Minimum Viable Product (MVP), Mobile App Development, Confluence
Senior Researcher and Head of Cybersecurity
2020 - 2025
National Institute for Research and Development in Informatics
- Mentored junior team members, helping them to develop their skills and advance their careers in cybersecurity research.
- Created and maintained detailed documentation of all research projects, providing clear and concise reports for management and stakeholders.
- Led the research team in conducting comprehensive security audits of most of our organization's systems, reducing cyber threats.
- Negotiated a partnership with a leading cybersecurity firm, resulting in access to cutting-edge tools and resources for the team.
- Implemented a new method for analyzing and prioritizing potential vulnerabilities, resulting in a 50% increase in efficiency.
Technologies: SQL, Software Architecture, CI/CD Pipelines, Architecture, Docker, Networks, Web Security, Confluence
Principal iOS Engineer
2024 - 2024
Property Finder FZ LLC
- Contributed to and implemented user-facing components following designs provided in Figma.
- Improved app performance by following user sessions in Instabug and other tracking tools.
- Participated in the code review process for peers and provided code improvement suggestions.
- Contributed towards increasing the code coverage by adding unit tests to the codebase.
- Improved security by implementing an SSL pinning system for the mobile app with remote configuration.
Technologies: iOS, Swift, Async/Await, iOS SDK, MapKit, APIs, Mobile Development, Mobile App Development, WiFi Direct, Confluence
Mobile Developer
2024 - 2024
Live EQ LLC
- Adjusted the existing app to the new business requirements by integrating new features.
- Tracked and fixed issues using reporting tools and profilers.
- Optimized loading times by looking into old code and refactored it to improve performance.
Technologies: Mobile Apps, Mobile UI, Mobile UX, iOS, Software Architecture, APIs, Mobile Development, Mobile App Development
Full-stack React/Swift Developer
2023 - 2024
SINES, Inc
- Developed and actively maintained the whole infrastructure, app feature cycle, and payments system.
- Improved trial conversion rate by integrating a streamlined sign-up experience.
- Improved user base by integrating SSO solutions (Apple, Google) across the ecosystem (iOS app, web app).
Technologies: iOS, Swift, Stripe, Stripe Checkout, Software Architecture, APIs, Mobile Development, Minimum Viable Product (MVP), Mobile App Development
Full-stack Developer (via Toptal)
2023 - 2024
Terra-bate LLC
- Developed a mobile app that served as a marketplace for eco-friendly products.
- Worked on creating the interface layer between the app, Stripe, and Plaid. This facilitated a cashback payment feature for the users.
- Oversaw the design process, architecture, and implementation of the app.
Technologies: Firebase, Stripe, Swift, MapKit, Software Architecture, APIs, Mobile Development, Minimum Viable Product (MVP), Mobile App Development
Point of Sales Expert
2023 - 2023
fiskaltrust consulting gmbh
- Developed features that helped the client adapt to the Spanish and Italian markets.
- Researched, planned, and implemented the transition from the first-generation hardware security module to the second-generation one.
- Planned and implemented the cash register receipt printing engine for the Italian market.
- Fixed issues that were present in the code repository and configured automated testing in the CI/CD pipeline.
Technologies: APIs, Confluence
Mobile Developer
2023 - 2023
Omnis Inc.
- Delivered the MVP that helped the client obtain financing and proceed to the next step for his startup.
- Defined specifications and project requirements, designed the user experience and user interface, and refined them by constantly iterating with the client.
- Oversaw and managed the other developers by reviewing pull requests, mentoring a junior developer, and leading status meetings.
Technologies: Amazon Web Services (AWS), APIs, Swift, SwiftUI, Software Architecture, Mobile Development, Minimum Viable Product (MVP), Mobile App Development
Freelance Software Engineer
2023 - 2023
Beyond Wealthtech Limited
- Developed a clean and easy-to-use UI to facilitate app usage.
- Integrated new UI components with existing modules and fine-tuned the performance.
- Added validation rules for user input to filter out unwanted outputs from the software.
Technologies: Azure DevOps
Experience
AI Filter App for iOS
https://apps.apple.com/ro/app/ai-filter/id6741488330• Built and launched an AI-powered iOS photo editing application from scratch, enabling users to transform images using prompt-based generative filters.
• Designed and implemented the full architecture, including UI, state management, and asynchronous processing for AI-driven image transformations.
• Developed intuitive user flows for uploading, previewing, and applying edits, optimizing performance for responsive rendering and smooth interaction. Integrated AI services to support real-time image generation and ensured scalability and maintainability of the codebase.
• Managed the full product lifecycle, from concept and design to App Store deployment.
• Designed and implemented the full architecture, including UI, state management, and asynchronous processing for AI-driven image transformations.
• Developed intuitive user flows for uploading, previewing, and applying edits, optimizing performance for responsive rendering and smooth interaction. Integrated AI services to support real-time image generation and ensured scalability and maintainability of the codebase.
• Managed the full product lifecycle, from concept and design to App Store deployment.
GlowUp App for iOS
https://glowup.com• Collaborated on the ongoing development of an AI-powered iOS photo generation app, focusing on maintenance, stability, and feature enhancements.
• Implemented new features for AI-driven image generation and editing workflows, improving overall functionality and user experience.
• Identified and resolved production issues, reducing crashes and ensuring consistent app performance.
• Refactored existing code to improve maintainability and scalability, while integrating updates to AI services and back-end APIs.
• Worked closely with product and design teams to deliver incremental improvements and optimize key user flows.
• Implemented new features for AI-driven image generation and editing workflows, improving overall functionality and user experience.
• Identified and resolved production issues, reducing crashes and ensuring consistent app performance.
• Refactored existing code to improve maintainability and scalability, while integrating updates to AI services and back-end APIs.
• Worked closely with product and design teams to deliver incremental improvements and optimize key user flows.
Video Widget App for iOS
https://videowidget.comCollaborated with another developer on an iOS application that transforms videos and Live Photos into looping Home Screen widgets, handling media processing, widget configuration, and UI customization flows.
Fintech Startup App for iOS
An MVP for a mobile app that was designed to facilitate loans between friends and family. I acted as the lead tech architect, and my responsibilities were defining project requirements, designing the user experience, managing the other developers, and implementing features myself.
Integrated Software | Next-generation Cash Registers
I architected and implemented a highly scalable application consisting of multiple microservices, a front-end component, and a cryptography provider. The scope of the app was to collect the data sent from the next-generation cash registers in Romania to validate the authenticity and integrity of the sales.
Digital Identity Wallet App for iOS
I managed the development of an iOS mobile wallet used to manage user identity. The app was designed to provide a secure and convenient way for users to manage and verify their digital identities. To ensure the app's security, I implemented advanced measures, including biometric authentication and encryption, to protect sensitive personal information. I also worked closely with UX designers to create an intuitive and user-friendly interface for managing and verifying digital identities.
Stock Market Automation Tool
I contributed as a freelance developer to a stock market automation tool to make it more accessible to non-technical users. I was tasked with building an intuitive GUI and integrating all the features present in the console version of the app.
Education
2019 - 2021
Master's Degree in Software Engineering
University of Bucharest - Bucharest, Romania
2016 - 2019
Bachelor's Degree in Computer Science
University of Bucharest - Bucharest, Romania
Certifications
JULY 2020 - PRESENT
Certified Ethical Hacker
EC-Council
JUNE 2015 - PRESENT
Cambridge Advanced English
University of Cambridge
Skills
Libraries/APIs
REST APIs, Stripe
Tools
Confluence, Stripe Checkout
Languages
Swift, SQL, TypeScript
Frameworks
SwiftUI, UIKit, MapKit, Combine, WidgetKit, CloudKit, iOS SDK, Core Data
Paradigms
Mobile Development, Azure DevOps, Testing
Platforms
iOS, Docker, Amazon Web Services (AWS), PostHog, Firebase, Bluetooth Low Energy (LE)
Storage
PostgreSQL
Other
Software Architecture, APIs, Secure Storage, Full-stack, Mobile Apps, Front-end, Web Development, Mobile Web, Responsive UI, Public-key Cryptography, User Interface (UI), User Experience (UX), Architecture, Networks, Web Security, Mobile UI, Mobile UX, WiFi Direct, Async/Await, Version Control, UI Testing, Supabase, Minimum Viable Product (MVP), Mobile App Development, CI/CD Pipelines, WebSockets, Bluetooth, Multithreading, SDKs, Mobile App Security, Native Mobile Apps
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