Carlos Ramos Senior iOS Developer
Portland, OR • iosdev@gmail.com • +1 503-555-0142
Profile Summary
- Senior iOS Developer with 8 years of experience building consumer-scale iOS apps on the App Store across consumer payments, peer-to-peer transfer, and merchant tooling, specializing in SwiftUI app architecture, Swift Concurrency, and Apple platform integration.
- Hands-on coverage across Swift 5.10, SwiftUI, UIKit, MVVM, Swift Concurrency, Core Data, XCTest, XCUITest, and Objective-C with strong fundamentals in protocol-oriented design, structured concurrency, and Apple human-interface fluency.
- Deep expertise in modular feature architecture, async-first data flow, testable view models, and privacy-first feature design, leveraging methodologies such as actor-isolated state with Sendable boundaries and design-system-driven SwiftUI surfaces to drive responsive, accessible, App-Store-ready iOS apps shipped at production quality.
- Engaged collaborator working cross-functionally with Design, Product, Backend, and Android teams in Agile and continuous-delivery environments, contributing to design-review forums, sprint planning, and architecture discussions with a pragmatic, ownership-first mindset.
- Emerging leader who shares technical excellence and fosters a culture of crash-free sessions and App Review readiness through PR reviews and component docs, while leading iOS community-of-practice sessions and authoring widely used view-model and feature templates.
Technical Skills
- Languages & Toolchain:
- Swift 5.10/6, Objective-C, structured concurrency, Sendable, macros, result builders, generics, Swift API design guidelines
- UI Frameworks:
- SwiftUI, UIKit, UIHostingController, UIViewRepresentable, Auto Layout, Combine, animations
- Architecture & Patterns:
- MVVM, MVC, MVI, VIPER, TCA, Clean Architecture, Coordinator, dependency injection, protocol-oriented design
- Concurrency & Reactive:
- Swift Concurrency (async/await, actors, AsyncSequence, Task, TaskGroup), Combine, GCD, OperationQueue
- Networking & APIs:
- URLSession, Alamofire, Apollo (GraphQL), REST, Codable, OAuth/OIDC, JWT, Sign in with Apple
- Persistence & Storage:
- Core Data, SwiftData, Realm, GRDB (SQLite), UserDefaults, Keychain, FileManager, offline-first sync
- Apple Frameworks:
- HealthKit, HomeKit, MapKit, CoreLocation, AVFoundation, PhotoKit, Vision, CoreML, ARKit, WidgetKit, App Intents, App Clips, APNs
- Release & Testing:
- XCTest, Swift Testing, XCUITest, snapshot testing, Xcode Cloud, Fastlane, GitHub Actions, App Store Connect, TestFlight, StoreKit 2
Education
Oregon State
University
B.S. in Computer
Science
Work Experience
Cash App
Senior iOS
Developer
- Drove iOS feature delivery on the Cash App iOS consumer app serving 55M monthly actives, shipping P2P payments, card management, and investing flows in mixed SwiftUI and UIKit across 35+ feature modules.
- Owned app architecture using MVVM with Coordinator, protocol-driven dependency injection, and a modularized SwiftPM workspace with feature libraries, refactoring 18 feature modules to a testable view-model boundary adopted by 6 squads across the app.
- Led the migration to Swift Concurrency with async/await with actors, AsyncSequence for streams, structured TaskGroup fan-out, and Sendable boundaries on shared state, retiring legacy Combine and GCD call sites across 220+ sites and dropping data-race incidents per quarter by 83%.
- Built the networking and data layer with URLSession with typed Codable clients, retry and offline-cache policies, and OIDC plus Sign in with Apple for auth and token refresh across 75+ REST and GraphQL endpoints, dropping failed-call rates by 44%.
- Shipped Apple platform integration through WidgetKit and App Intents, Live Activities on the lock screen, APNs-driven background refresh, and CoreLocation-gated transfer prompts across 9 surfaces, lifting widget engagement by 27%.
- Drove performance and memory work with Instruments Time Profiler, Allocations and Leaks for retain-cycle hunts, and lazy-loaded feature modules, pulling cold launch from 2.4s to 1.1s and holding crash-free sessions at 99.7% across the rollout.
- Owned iOS testing with XCTest with Swift Testing for unit and integration suites, XCUITest for end-to-end flows, and snapshot tests on the SwiftUI surface, lifting unit coverage from 51% to 88% and dropping regression escapes per release by 61%.
Nike
iOS
Developer
- Built the local persistence and offline-sync layer with Core Data with NSPersistentCloudKitContainer, Keychain-backed secure storage for run history, and FileManager-cached media assets, supporting 2.3M records synced offline and cutting sync-conflict incidents by 58%.
- Owned App Store distribution and release engineering with Fastlane with Xcode Cloud, automated code-signing, App Store Connect metadata, and TestFlight rings for staged rollout, shipping 40+ App Store releases and rolling out a StoreKit 2 subscription tier that reached 180k paying subscribers.
- Modernized legacy UIKit surfaces with UIHostingController bridges, diffable data sources on UICollectionView, and Auto Layout cleanup, migrating 38 screens to SwiftUI without breaking the existing UIKit navigation stack.
- Partnered Design, Backend, and Android on the shared product roadmap, authored 5 iOS architecture RFCs adopted across the consumer app, and onboarded 3 junior iOS developers through PR reviews and pair programming.