Notes on mobile engineering, AI, and language learning.

Ievgen (Eugene) Goloboiar , iOS Engineer

I have been working as an iOS developer since 2013, starting with small applications and later building SDKs and apps used by millions of users.

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Latest posts

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October 17, 2026 · 15 min read

some vs any in Swift: The Difference and When to Use Each

Understanding existential and opaque types through checkout, SDK design, SwiftUI, and Swift runtime internals.

October 10, 2026 · 12 min read

How to Clean Xcode DerivedData and Why It Grows to Tens of Gigabytes

Why Xcode DerivedData grows to tens of gigabytes on a Mac, how to inspect and clean it (Xcode Settings, Terminal, Xcode 27, free tools), and a small zsh script called `xcode-dd` for a one-command overview.

August 29, 2026 · 15 min read

Experiments with Token Usage and Optimization

A personal experiment with Codex session logs: where tokens actually go, how I measured usage, and what I changed in the way I manage context.

August 22, 2026 · 10 min read

iOS Logging and Analytics: A Practical Guide

Logging and analytics aren't a checkbox. They do different jobs, and if you don't understand which, all that instrumentation quietly turns into noise you can't get anything out of.