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Sergei M.
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Sergei M.

Senior iOS Engineer | Android, Frontend, Backend | AI-Assisted Develop

Overview Senior engineer with 20+ years of hands-on software development experience, including 10+ years in mobile. My main focus is iOS, with additional hands-on work across Android, frontend, backend, desktop systems, and performance-critical code. I work both manually and through AI-assisted development workflows. I use AI to speed up specification, planning, implementation, and iteration, but I stay fully hands-on when architecture, code quality, reliability, legacy code, or low-level control matter. I help build and improve real products across the full delivery chain: iOS apps in Swift / SwiftUI, plus legacy Objective-C / UIKit codebases Android development and cross-platform product work Frontend interfaces and production web UI Backend APIs, integrations, Firebase, REST, WebSockets, and supporting services AI-powered features such as ChatGPT integrations, OCR, image recognition, and on-device ML BLE / hardware integrations, including ESP32 / Arduino-based devices C/C++ components for performance-critical and system-level work My focus is always the same: clean code, reliable architecture, complete functionality, and production-ready delivery across blurred platform boundaries.

🇵🇱Warsaw, Poland$30/hr100% JSS5.00 (14)Since Oct 2017

Earnings and projects

MRR
$3.9k

Last 6 months ÷ 6

World#8,412 / 412k
🇵🇱Country#122 / 2,852
Revenue, last 30 days
$0

Last 6 months: $23k

Total earnings
$159k

Billed in all: $166k

World#21,674 / 412k
🇵🇱Country#325 / 2,852
Per project
$8.8k

$12k in the last 6 months

World#18,574 / 412k
🇵🇱Country#247 / 2,852
Projects, last 6 months
2
0% fixed100% hourly
World#88,918 / 412k
🇵🇱Country#610 / 2,852
Projects in all
18

Across 20 contracts

45% fixed55% hourly
World#143,608 / 412k
🇵🇱Country#1,063 / 2,852

Earnings, last 30 days

$166kNothing earned in the last 30 daysBilled in all, before Upwork's fee · drag across the chart to see what was earned in any stretch
$162k$164k$166k$168kOct 8Oct 23Nov 7

Skill rankings: Top 2% in CSS

Ranked by MRR among everyone on Upwork with the skill.

  1. #4tvOS66 freelancers · 🇵🇱 #1Top 6%
  2. #5Mac OS App Development159 freelancers · 🇵🇱 #1Top 3%
  3. #29Arduino1,007 freelancers · 🇵🇱 #1Top 3%
  4. #37Objective-C1,282 freelancers · 🇵🇱 #2Top 3%
  5. #39ESP32780 freelancers · 🇵🇱 #1Top 5%
  6. #42SwiftUI951 freelancers · 🇵🇱 #1Top 4%
  7. #96Kotlin3,021 freelancers · 🇵🇱 #2Top 3%
  8. #135AI Implementation2,382 freelancers · 🇵🇱 #2Top 6%