Leonid Humeniuk
Staff Software Engineer
I'm an iOS Software Engineer from Ukraine, currently based in Berlin, with 10 years of experience building apps across a wide range of domains — from IoT startups and life-tracking apps to photo and video editing tools, and currently approaching my second year at eBay, one of the world's largest e-commerce platforms.
Throughout my career, I've worked across the full spectrum of iOS technologies, including AVFoundation, Core Graphics, Core Text, Metal, Core Bluetooth, and Maps — gaining hands-on expertise that goes well beyond the typical iOS stack.
I've contributed to teams of all sizes, from lean two-person startups to large engineering organizations. Having seen how differently teams work across scales, I've noticed that build time is one of those silent productivity killers — small things that quietly pile up and slow everyone down, yet rarely get the attention they deserve.
I'm passionate about growing the next generation of engineers through mentoring, and I actively drive the internal European iOS community at eBay — organizing knowledge sharing sessions and talks that keep our engineers connected and growing across the continent.
Faster iOS Builds: Measuring Performance and Uncovering Hidden Compiler Costs
Slow builds impact more than developer experience—they reduce productivity, slow feedback cycles, and increase CI infrastructure costs. As iOS codebases grow, even small increases in compile time can result in thousands of lost engineering hours.
The most expensive build-time bottlenecks are often the least obvious. Many originate from Swift compiler behavior, language features, and everyday coding patterns rather than the build system alone.
This session demonstrates how to measure and analyze iOS build performance using Xcode, compiler diagnostics, and build analysis tools. Through real-world examples, we'll uncover hidden compiler costs, explore practical optimization techniques, and discuss how AI can help engineers interpret build data, identify bottlenecks, and accelerate performance investigations.