Vladyslav – Golang, Kubernetes, ElasticSearch

Backend for the package sorting centers in the delivery network of a large e-commerce marketplace (30M+ customers). The services match packages to chutes on the sorting machines and expose the APIs that machines and operators use to route every package to its destination.

• Co-designed and led a zero-downtime migration of the warehouse storage domain.
• Built the new service's storage and shelf domain, with indexes tuned on production access patterns.
• Built an X-ray passage (security screening) service from scratch and delivered the feature end to end.
• Shipped sorting-floor features: infeed and induct APIs, label reprinting and AGV robot integrations.
• Rolled out OpenTelemetry tracing and Prometheus metrics.
• Regularly led epics from solution design to production rollout.

A platform that sells a large e-commerce marketplace's assortment on foreign marketplaces and through sales partners. Products are listed per partner with mapped attributes, prices and stock, and synced to partner APIs.

• Built Go Kafka consumers with retries and dead-letter topics for partner product, price and stock sync.
• Built Kotlin/Spring Boot APIs for partner products, prices, inventory and per-channel campaign settings.
• Published price changes through a transactional outbox, so partners never saw an uncommitted price.
• Streamed approved partner products into Elasticsearch for internal search.
• Added audit logging across the partner APIs and critical alerts with Elasticsearch alerting.

The core product catalog of a large e-commerce marketplace (30M+ customers): product content, prices and stock, validation and tagging, and the listings and localized content used to sell abroad. It is the source of truth for other teams' systems.

• Owned major parts of the Kotlin listing-indexing pipeline, including bulk migrations of hundreds of thousands of listings.
• Built a broken-size detection service from scratch in Go.
• Implemented fault-tolerant content migrations with Go Kafka consumers and per-record isolation.
• Implemented distributed tracing across Kafka consumers and APIs.
• Extended the translation API for multi-locale catalogs: new locales, content versioning, migration endpoints.
• Worked on the ChannelAdvisor partner bridge: idempotent cancellations and refunds, stock updates, partner onboarding.

Cloud-native, API-first core insurance platform of a major US insurer, focused on the quote flow: starting, validating and rating quotes.

• Configured business rules for quote initiation, validation and rating, and the insurance-flow attributes.
• Implemented services that let authorized users audit quote rating.
• Configured users, roles and privileges.