Serhii H.Private profile: Upwork shows its earnings only to signed-in members, so we check it every few weeks, not daily. MRR here is a rough estimate (Upwork's six-month earnings ÷ months active). Last read Oct 14, 2026.

70 contracts and 7,600 hours on Upwork. I build, develop, architect, audit iOS and iPad apps in fintech, real-time messaging, live marketplaces, and social - including the SDK behind a major US sports league's app (10M+ downloads). 15 years of shipping native Swift and SwiftUI, Objective-C and UIKit I take on hard problems and complex architecture. I also fix apps that are broken or stuck. I write code that's stable and easy to maintain Most of my work falls into two situations: First: a startup needs one engineer to own iOS from day one - I design the architecture, build the UI in SwiftUI, wire up integrations, and ship it to the App Store Second: there's an existing app, and something is broken or stuck. Often it's old Objective-C code, a messy architecture, or both. I get productive fast and fix it I've done both across 70 projects. I've seen most ways an iOS app can be built - and most ways it can go wrong Performance is where I spend the most attention. I profile the app in Instruments and measure real timings - launch time, frame drops, memory use. I move heavy work off the main thread, so scrolling stays smooth and the UI never blocks. I optimize screens so content appears fast and memory stays flat, even in a long session. I track crashes in analytics like Crashlytics, and I watch crash-free rate release over release CODE AND APP AUDIT I review the source code and the running app, and you get a written report: architecture, performance, security, crashes, and what to fix first. More and more often it's AI-generated code after vibe coding. The app works, but it's hard to change, and nobody fully knows what's inside. I clean it up and give it a structure your team can build on WHAT I BUILD Social and dating: swipe-based matching apps, TikTok-style video feeds, in-app chat Fintech and payments: subscriptions, in-app purchases, checkout flows AI-powered products: apps built around OpenAI and LLM features with long-term memory Live commerce and marketplaces: live auctions and real-time bidding, similar to Whatnot or StockX Media and streaming: camera apps, video pipelines, background audio Location-based services: apps built around maps and real-time location I also built the SDK behind a major US sports league's in-stadium experience (facial recognition that finds your photo automatically among thousands of fans). It runs inside an app with over 10 million downloads HOW I WORK We start with a call. I ask clarifying questions early, while changes are still cheap. I check your requirements against Apple's guidelines, and we adjust the idea and scope if needed. We also set up a fast channel and overlapping work hours, so we can talk in real time. You get a written scope, priorities, stages and dates before any code exists During development, you get regular working versions of the app through TestFlight, plus visible progress in a task tracker. That way you always know what we have at this stage I write code that's easy to read and maintain, years after I'm off the project. Near release, I handle the App Store submission and fix any review issues that come up. Your team can pick it up later and keep building, without a rewrite I'm with you from the first call to release - and after Based in Southeast Asia (GMT+7). Flexible hours - I overlap with US, EU, and APAC teams TECHNICAL Swift, SwiftUI, UIKit, Objective-C, Combine, async/await, MVVM and modular architecture Networking and real time: REST, GraphQL, WebSockets, Firebase, push and VoIP notifications Payments: Stripe, Apple Pay, StoreKit in-app purchases and subscriptions with server-side validation AI and ML: OpenAI and LLM integrations, Core ML, Vision, on-device inference Media: AVFoundation, camera and video pipelines, background audio, streaming SDKs Data and graphics: Core Data, SwiftData, Metal, MapKit and location services Delivery: CI/CD, Instruments, Xcode Cloud, XCTest, GitHub Actions, TestFlight, App Store review When you need a small team, I can handle the API layer too - Node.js, TypeScript, PostgreSQL, Redis, AWS. You get one engineer accountable for the full stack, without coordination overhead. Send me the details - the deadline, the bug, the codebase. I'll tell you whether I'm the right fit, what it will take, and how long