Aleksandr K.
Senior Web & Mobile Developer | Scalable & High-Load Systems
For 15+ years, I’ve built web and mobile apps that run reliably in production — not just demos. Clients come to me when systems need to stay stable under load and behave predictably. I focus on architecture and delivery that actually work in real conditions. I’ve delivered 100+ projects, including high-load systems with millions of users. My experience covers VPN & cybersecurity solutions, banking software, AI tools, real-time tracking systems, and scalable mobile/web platforms with complex functionality — along with other non-trivial systems. Tech: • Swift (UIKit / SwiftUI), Kotlin (Jetpack, Coroutines) • React (Next.js), Vue • Node.js (NestJS / Express), PHP (Laravel / Yii2) • WebSockets, TCP/UDP • REST / GraphQL APIs • Stripe / PayPal • Firebase, Amplitude, AppsFlyer, RevenueCat • OpenAI, Gemini, Claude, vector DBs • JWT, OAuth2, encryption, secure storage I handle architecture and key decisions myself. If needed, I involve additional developers — always transparently. Process is straightforward: define scope → plan → build → test → release → support. No overengineering, no surprises. If you need help with a new project or improving an existing one — send a short description, and I’ll quickly outline the best way to approach it.
Earnings and projects
Last 6 months ÷ 6
Last 6 months: $1k
Billed in all: $237,040$237k
$346 in the last 6 months
Across 32 contracts
Earnings, last 30 days
Skill rankings: Top 11% in RxJava
Ranked by MRR among everyone on Upwork with the skill.
- #8RxJava73 freelancers · 🇺🇦 #2Top 11%🇺🇦#2 of 17
- #21Android NDK94 freelancers · 🇺🇦 #4Top 22%🇺🇦#4 of 10
- #163Android SDK805 freelancers · 🇺🇦 #19Top 20%🇺🇦#19 of 90
- #719Kotlin3,021 freelancers · 🇺🇦 #54Top 24%🇺🇦#54 of 224
- #815Swift3,634 freelancers · 🇺🇦 #76Top 22%🇺🇦#76 of 314
- #991iOS3,908 freelancers · 🇺🇦 #99Top 25%🇺🇦#99 of 321
- #1,142Android4,975 freelancers · 🇺🇦 #119Top 23%🇺🇦#119 of 371
- #1,599Java8,313 freelancers · 🇺🇦 #106Top 19%🇺🇦#106 of 441