About
Charles Feinn is an accomplished AI/ML Engineer and Mobile Architect with over 12 years of experience building and scaling production systems. He holds an M.S. in AI/ML and has a proven track record of leading technical teams to deliver high-impact platforms, including scaling a dating app to 25K monthly active users and creating reusable AI infrastructure that reduced development time by 50%. An expert in LLM integration, iOS development, and full-stack system design, Charles is adept at driving innovation and achieving measurable results in complex technical environments.
Work
Remote, N/A, US
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Summary
Led AppSimple LLC as Founder and Principal Software Engineer, driving innovation in AI/ML and mobile development to deliver advanced solutions for diverse client needs.
Highlights
Designed and deployed a comprehensive LLM Server with multi-provider support (OpenAI, Claude, Gemini), integrating pipeline processing and circuit breaker patterns for robust production deployment on Modal.com with Cloudflare tunneling.
Spearheaded development of the ContactCapture iOS app, leveraging AI for business card extraction and custom camera integration, while implementing secure Firebase authentication across Google, Apple, and Email providers.
Developed ASimpleAuthKit Swift package, achieving 95%+ test coverage for production-ready Firebase authentication and reducing project implementation time by 2-3 weeks.
Launched two highly-rated meditation apps, Guided Mind (295K+ installs, 4.7 rating) and Bodhi Mind (100K+ sessions, 4.6 rating), incorporating offline audio, HealthKit integration, and subscription models.
Remote, N/A, US
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Summary
Progressed from Mobile Developer to Lead Mobile Developer, spearheading the development of 5 production iOS/tvOS applications for thousands of dental professionals.
Highlights
Led a mobile team in developing 5 production iOS/tvOS applications, with the flagship app achieving a 17-minute average session duration, 4.9 App Store rating, and 30% churn reduction.
Architected SpearUIFramework and AuthFramework, reducing new app development time by approximately 50% by standardizing 10K+ lines of authentication, UI components, and data management across the mobile portfolio.
Engineered and implemented a robust CI/CD pipeline using Fastlane and GitHub Actions, slashing deployment time from 3 hours to 15 minutes and processing 50+ weekly builds with zero environment-related failures.
Developed an advanced offline video download system and cross-device sharing via MultipeerConnectivity, enhancing user experience with GraphQL-powered search and real-time synchronization.
Remote, N/A, US
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Summary
As CTO, launched and scaled a dog-lover dating platform, overseeing technical strategy and product development from inception to significant user adoption.
Highlights
Launched a new dog-lover dating platform from the ground up, rapidly scaling it to 25,000 monthly active users and 3,000 daily active users, achieving a 4.7 App Store rating and 3-minute average session duration.
Designed and implemented a scalable serverless Firebase backend capable of handling thousands of daily matches, real-time chat, automated matching algorithms, and content moderation.
Directed Android platform expansion, achieving 100% feature parity with iOS within 2-3 months through effective vendor management and technical oversight.
Burlingame, CA, US
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Summary
Founded and led a music technology startup, scaling user base to over 1 million and securing significant investment and strategic partnerships.
Highlights
Founded and scaled a music technology startup to over 1 million active users, launching 1,000+ mobile apps that generated 1.4M+ downloads with notable clients including major record labels and artists.
Earned the prestigious DEMOgod Award at DEMOfall 2008 (top 10 out of 2,200 applicants) for an innovative collaborative music platform.
Secured $400K in angel investment and established strategic partnerships with industry leaders (TuneCore, IODA, BandsInTown), guiding a 10+ person team through a successful pivot to a mobile app platform.
Education
Publications
Languages
English
Spanish
Skills
AI/ML
DSPy, OpenAI API, Anthropic Claude, Hugging Face, LLM evaluation, Prompt Optimization, FastAPI, LLM Integration, AI Infrastructure.
Mobile Development
Swift, SwiftUI, iOS, Objective-C, Core Data, Firebase, StoreKit, AVFoundation, GraphQL, Mobile Architecture.
Backend Development
Python, Node.js, REST/GraphQL APIs, Microservices, Firebase, Docker, CI/CD, Full-stack System Design.
DevOps
GitHub Actions, Fastlane, Modal.com, AWS, Prometheus, Automated Deployment, CI/CD Pipeline Management.
Leadership & Management
Technical Leadership, Team Leadership, Startup Leadership, Project Management, Strategic Planning, Vendor Management.
Product Development
Product Launch, Scalability, System Design, Problem-Solving, Innovation.