David Rynn

Senior iOS Developer

Brooklyn, NY · davidrynn@gmail.com · LinkedIn · GitHub

Professional Summary

Senior iOS Developer with 9 years of experience shipping high-quality native mobile apps used by millions across fintech, healthcare, and media platforms. Specialized in Swift, SwiftUI, and product-driven development — from concept and design collaboration through implementation, experimentation, and measurement. AI-forward mobile engineer with a proven record of applying Generative AI and large language model (LLM) tooling to accelerate software delivery speed and quality, improve developer workflows, and ship better product outcomes. Recognized leader in mobile AI enablement: led Chase's global AI Ambassador Mobile Chapter, driving adoption of Model Context Protocol (MCP), custom agent workflows, and AI coding tools across distributed engineering teams. Strong cross-functional collaborator who works closely with designers, product thinkers, data science and machine learning partners, and customers to build and grow mobile products.

Core Technical Skills

Swift, SwiftUI, GraphQL, Apollo APIs, Structured Concurrency (async/await), Combine, Stripe, XCTest, Xcode Instruments, MVVM-C, RxSwift, Redux, CocoaPods, SPM, Objective-C, Bitrise (CI/CD), GitHub/GitLab/Bitbucket, Jira, Charles Proxy

AI & Agent Tooling: Generative AI, LLM-assisted development, Model Context Protocol (MCP), GitHub Copilot Skills, Claude Code, OpenHands, Apple FoundationModels, Apple Intelligence, Windsurf, Copilot, Cursor

AI Workflow Strengths: AI-assisted SDLC design, agentic workflow design, custom instruction/agent/skill authoring, prompt and context engineering for software delivery, developer enablement and AI best-practice rollout

Certifications: AWS Certified Cloud Practitioner; Introduction to Model Context Protocol (Anthropic)

Experience

Fieldlight Interactive — Independent iOS Product Engineer 2026 – Present

Built and released an independent iOS app ("Clear Next Step") from concept through App Store launch, owning product definition, UX flow, architecture, implementation, testing, release preparation, and iteration.
Designed a focused workflow that helps users move from an unstructured brain dump to a single actionable next step, balancing emotional validation with low-friction task completion.
Implemented the app using Swift/SwiftUI and Apple Intelligence/Foundation Models, exploring practical on-device AI patterns for user-facing productivity workflows.
Used AI-assisted development tools to accelerate implementation, test edge cases, evaluate UX alternatives, and improve release readiness.

Chase — Senior iOS Engineer Nov 2023 – Present

Owned and iterated on user-facing payment flows serving 80M+ customers, modernizing UIKit systems with MVVM/Coordinator.
Refactored networking layer, contributing to a 12% app-wide stability improvement.
Resolved critical defects in payments flow, increasing conversion stability by 5%.
Used Xcode Instruments to diagnose performance bottlenecks and presented iOS performance profiling practices to Chase mobile engineers.
Contributed to Chase's Swift Concurrency working group and delivered internal talks to help mobile teams adopt async/await patterns and safer concurrent architecture.
Delivered secure API integrations and led onboarding workshops to accelerate new-engineer ramp-up.
Led the global AI Ambassador Mobile Chapter — the first mobile-focused AI leadership role at Chase — driving adoption of AI-assisted software development, MCP, agent frameworks (Claude Code, OpenHands, Copilot), and AI coding tools to improve engineering quality and delivery across distributed teams.
- Established mobile-focused AI best practices across global teams by creating custom instructions, agents, and reusable skills for iOS development, debugging, and test workflow acceleration.
- Partnered with Chase's broader AI4Tech community as mobile lead to align regional teams, share playbooks, and deliver learning decks for engineering org-wide AI education.

Maven Clinic — Senior iOS Engineer Jul 2022 – Oct 2023

Shipped high-quality native SwiftUI debit card feature integrated with Stripe, from concept through App Store release.
Built subscription and payment workflows with SPM and MVVM/Coordinator.
Mentored junior developers and collaborated cross-functionally to improve the product and hiring process.

Capital One — iOS Engineer Jun 2021 – Jun 2022

Developed customer-facing activation and onboarding features with RxSwift, Combine, and Redux.
Migrated legacy Objective-C to Swift, reducing crash rates and improving user experience.
Created onboarding demos and documentation, cutting new-engineer ramp-up time by 30%.

Small Planet — iOS Engineer (Consultant) Feb 2021 – Jun 2021

Built data-scraping integrations for retail rewards app. (Contract)

Prolific Interactive (acquired by WeWork) — iOS Engineer Jan 2019 – May 2020

At Prolific (Jan–Jul 2019): Shipped native iOS apps for clients in fintech, retail, and media using Swift, Objective-C, and RxSwift.
At WeWork (Jul 2019–May 2020): Built onboarding and activation features with GraphQL and RIBS; owned internal CocoaPods and coding standards.

NYC Dept. of Information Tech & Telecom — Mobile Developer Jan 2016 – Dec 2018

Lead developer for Notify NYC, a user-facing emergency notification app with 25K+ active users.
Built and maintained mobile notification delivery features to publish timely emergency alerts to city residents.
Designed MVVM architecture and delivered iOS best practice talks to the engineering team.

Prior career as Public Defender (30+ jury trials) — developed leadership, communication, and analytical skills.

Education

Flatiron School – iOS Programming (Immersive) | NYU – Java I & II | UCSB – B.A. Law & Society | Lewis & Clark Law School – J.D.

Speaking, Leadership & AI Projects

AI Ambassador, Chase Bank — Led mobile AI chapter; ran AI hackathons; evaluated and piloted MCP, GitHub Copilot Skills, Claude Code, OpenHands, Copilot, Windsurf, and Cursor across the mobile engineering org to improve AI developer productivity.
Speaker, Chase iOS Engineering (Internal) — delivered talks on Swift Concurrency adoption and async/await migration patterns; contributed to the iOS concurrency working group.
Speaker, iOSoho NYC Meetup (2025) — presented on Apple FoundationModels/Apple Intelligence; showed practical on-device AI patterns and demoed an app that generated lightning talks from prompts.
Built AI-assisted side projects spanning procedural terrain experiments in Unity, a DSA study app, and an in-progress game prototype to deepen hands-on Generative AI and LLM product integration skills.
Created "Clear Next Step" as both a custom GPT and an Apple Intelligence app concept focused on reducing decision paralysis through actionable next-step guidance.
Speaker, iOSoho NYC Meetup (2021) — gave lightning talks on SwiftUI Charts and Regex in Swift.