I’m Mark, a backend engineer

Reworked the core of a mobile measurement platform (MMP), replacing hardcoded attribution logic with per-app flows whose steps can be added, removed, or reordered without deploys.

Achieved an attribution match rate of ~30–35%, compared with ~20% using the previous tracker.

Built an internal API gateway for authentication, authorization, and user management across several products; helped consolidate team workflows into one interface, automating manual work and reducing coordination overhead.

Supported adoption through test campaigns run by internal teams before broader use.

Set up server infrastructure, CI/CD, and monitoring with Grafana and Prometheus; took responsibility for uptime and production failures, investigating issues through logs and metrics.

Split the order-creation flow (~1.5M events/day) into domestic and cross-border queues for international expansion; built an in-memory office-geo cache (inverted index, O(1) lookup) to keep country resolution off the hot path.

Delivered supplier-return order creation in the repack domain end to end after the original owners left: recovered context from internal docs and git history; negotiated an API extension with the defects team; decomposed work for frontend, mobile, and DB engineers.

Interviewed 20 trainee candidates and mentored a team of 5; 3 stayed with the company as engineers.

Contributed across 6 warehouse domains: repack, defects, checkpoint, order creation, lost & found, and write-off disputes; held maintainer permissions, including merges to the main branch, in several repositories.

Built REST APIs and JWT-based authentication for early-stage products.

Designed MongoDB data models and integrated Cloudinary for image hosting within a zero infrastructure budget.

When I first joined, I was assigned to a new project: a mobile application for a CRM system. The design was quite complex because the app targeted multiple platforms, including iPad. One of the challenges was the large amount of data that had to be passed between screens. After reviewing the available options, I chose Redux over MobX for its stricter data flow, which helps prevent accidental state changes.

The layout had 23 screens with low component reusability due to design constraints. Solved it with compound components — built skeleton structures that could be composed via children rather than duplicated.

herald — zero-dependency User-Agent parser, used in production across company services.

logger — request-scoped structured logging on top of zerolog.