Vitaliy

Vitaliy Kuzmich
Senior Golang Engineer | Microservices · gRPC · Kubernetes
[відкрити контакти](див. вище в блоці «контактна інформація»)• [відкрити контакти](див. вище в блоці «контактна інформація») • github.com/vitaliy-kuzmich

1,500× faster critical path · Release cycle: 2 months → 1 day · Runs on router-class hardware ·
12 years of backend and systems work

PROFESSIONAL SUMMARY
Go engineer with twelve years in backend and systems development. Usually brought in when infrastructure
cost, latency or reliability has become a number someone above engineering is asking questions about.
Writes concurrent services that hold their throughput under load and run on a fraction of the hardware they
replace. One of them, an open-source cloud-storage server, was built to run on a router. The rest of the stack
comes with it: gRPC and REST APIs, Postgres and Kafka, Kubernetes, and the Linux underneath.

SELECTED ACHIEVEMENTS & IMPACT
 Made a critical processing path roughly 1,500× faster with caching, denormalised storage and concurrent
workers. An approved hardware expansion budget was returned unspent.
 Rewrote resource-hungry services as lean Go binaries. The memory and CPU footprint dropped far enough
to run several per instance and consolidate the fleet.
 Cut the release cycle from two months to one day by replacing manual releases with containerised CI/CD
on Docker and Kubernetes.
 Built a production server that runs on router-class hardware, which proved the architecture in a place
where a conventional stack would not fit at all.
 Delivered a greenfield product from empty repository to production in under three months, bringing the
launch forward by a quarter.
 Unified 20+ external service integrations behind one concurrency-safe layer, and partner onboarding went
from weeks to days.
 Architected a high-load exchange so a traffic spike is handled by scaling out rather than by an incident.

TECHNICAL SKILLS
Languages: Go (Golang) 1.2x, SQL, TypeScript (TS), JavaScript (ECMAScript ES6+ / ES2023), Bash
Go Ecosystem: net/http, Gin, Echo, Fiber, Chi, gorilla/mux, gRPC and Protocol Buffers, GORM, sqlx, pgx, Ent,
database/sql, goroutines, channels, context, sync and sync/atomic, worker pools, Go modules, Cobra, Viper,
Wire, go-redis, Sarama and segmentio/kafka-go, NATS
Testing & Tooling: Go testing package, Testify, gomock, table-driven tests, testcontainers-go,
benchmarking, race detector, pprof profiling, golangci-lint, go vet, GoReleaser, Delve, TDD, code review
Architecture: Microservices, RESTful API design, gRPC service contracts, GraphQL, event-driven architecture,
Domain-Driven Design (DDD), CQRS, clean and hexagonal architecture, SOLID, concurrency patterns, high-
load and low-latency systems, horizontal scaling, circuit breakers and graceful degradation, WebSocket
services, custom binary and TCP protocols
Data & Messaging: PostgreSQL, MySQL, ClickHouse, MongoDB, Redis, Elasticsearch, Apache Kafka,
RabbitMQ, schema design, indexing, query optimisation, migrations, caching strategies, denormalised data
models
Front-End: TypeScript, JavaScript (modern ECMAScript), React.js (Hooks, Redux Toolkit), Angular (Angular
2+, RxJS) and AngularJS, Vue.js, HTML5, CSS3, SASS, Bootstrap, Webpack, Vite, responsive design, single-page
applications (SPA), REST and gRPC-Web client integration
DevOps & Cloud: Docker, Docker Compose, Kubernetes (K8s), Helm, Jenkins, GitHub Actions, GitLab CI/CD,
AWS (EC2, S3, RDS), Nginx, GNU/Linux system administration, OpenWrt (build from source), systemd,
Prometheus and Grafana, OpenTelemetry, structured logging, Sentry, Git
Security: OAuth 2.0, JWT, SAML 2.0 single sign-on, TLS/SSL, RBAC, secure coding practices, information-
security engineering background (MSc)
Also works with: Java and Spring, Python, Node.js and TypeScript on adjacent services; embedded C on IoT
projects
PROFESSIONAL EXPERIENCE

Senior Backend Engineer — Purchase Order Management Platform
Confidential Client (NDA) · Enterprise Procurement | 10.2023 – 12.2024
 Delivered new domain functionality across the stack: service APIs, business-rule layer, relational schema
evolution and the TypeScript/JavaScript client.
 Decomposed monolithic legacy modules into isolated, testable services with explicit contracts and
predictable failure modes.
 Worked with product stakeholders to turn business requirements into technical designs and shipped
reviewable increments.

Senior Engineer — Checkout & Biometric Authentication Module
Confidential Client (NDA) · Retail Technology | 01.2022 – 08.2022
 Built a fingerprint-authentication component for a retail checkout system: native device communication,
verification service and operator interface.
 Implemented token-based authentication and fine-grained permissions around sensitive point-of-sale
operations.
 Handled packaging, deployment, on-site debugging and client handover.

Senior Backend Engineer — Feedback SaaS Platform (Greenfield)
Confidential Client (NDA) · SaaS Product | 09.2021 – 11.2021
 Designed and built a customer-feedback service from an empty repository: domain model, API contract,
persistence layer, background workers and release pipeline.
 Owned architecture and stack selection and delivered a production-ready MVP within a fixed deadline.

Senior Backend Engineer — Fleet Management & Telematics Platform
Confidential Client (NDA) · Logistics & Transportation | 07.2021 – 01.2022
 Maintained and modernised a large legacy fleet-tracking platform ingesting continuous telematics data,
with no downtime for active operators.
 Resolved production defects rooted in concurrency, data consistency and third-party device integrations.
 Delivered both backend fixes and front-end improvements as the sole owner of the module.

Senior Engineer — Healthcare ERP & Cloud Analytics (ClickHouse)
Confidential Client (NDA) · Healthcare & Cloud | 09.2020 – 04.2021
 Developed new modules and fixed defects in a production ERP handling sensitive patient and billing data.
 Built a cloud analytics service on ClickHouse for high-volume ingestion and reporting workloads.
 Optimised queries, indexes and access patterns to cut latency on the platform's heaviest screens.

Senior Engineer / DevOps — Developer Tooling Platform
Confidential Client (NDA) · Atlassian Ecosystem | 12.2019 – 06.2021
 Implemented core extension components from scratch against a third-party platform API and integrated
them with internal enterprise services.
 Owned the delivery infrastructure: Docker images, Jenkins CI/CD pipelines, environment provisioning and
release automation.
 Acted as the messaging subject-matter expert on a parallel engagement, tuning broker-based integration
flows for reliability and throughput.

Software Architect & Lead Developer — High-Load Cryptocurrency Exchange
Confidential Client (NDA) · FinTech / Trading | 03.2018 – 06.2018
 Designed the microservice architecture of a high-load exchange: order-processing pipeline, denormalised
data model, Redis caching layer and asynchronous message bus.
 Defined horizontal scaling, fault-isolation and consistency strategies for heavily concurrent trading
workloads.
 Led technical direction and reviewed performance-critical, concurrency-sensitive code paths.

Backend Engineer & Consultant — Security, Commerce and Blockchain
Confidential Clients (NDA) · Multiple Industries | 12.2017 – 03.2019
 Implemented multi-provider SAML 2.0 federated single sign-on inside an enterprise security stack.
 Delivered backend features and analytical SQL reporting for an e-commerce platform.
 Consulted on distributed system design and integration architecture for fintech clients, then built the
services that followed.
Full-Stack Engineer & Linux Administrator — Integration Library, Risk Platform, ERP
Confidential Clients (NDA) · Enterprise & FinTech | 01.2015 – 05.2017
 Architected a highly concurrent integration library that connected a large enterprise platform with 20+
external services and protocols.
 Built a clustered financial risk-calculation application, owning both the computation engine and the user
interface.
 Delivered an ERP platform from scratch and ran its production Linux infrastructure (Nginx, application
servers, mail, DNS, FTP).

Software Engineer — Trading Platform, Real-Time Streaming and IoT
Confidential Clients (NDA) · Trading & IoT | 04.2013 – 09.2015
 Developed back-office services, order processing, reporting and data-access layers for a clustered trading
broker platform, plus an internal load-testing tool.
 Built real-time clients streaming live market and GPS data over WebSocket and custom binary protocols.
 Integrated IoT hardware and mobile devices with backend tracking services and REST APIs.

OPEN-SOURCE & PERSONAL ENGINEERING PROJECTS
github.com/browsefile — Lightweight self-hosted cloud-storage server written in Go: a Nextcloud
alternative engineered to run on low-resource devices such as USB-equipped routers.
OpenWrt (built from source) — Builds and maintains custom firmware images for edge deployments of Go
services.
Upstream contribution — Reported and fixed a defect in a widely used open-source security framework,
found during a ProFTPD and SQL integration.

EDUCATION & PROFESSIONAL DEVELOPMENT
Master of Science, Information Security Engineering — University of Technology, Dnipro, 2007 – 2012
Professional Software Engineering Program (certified) — SoftServe, 2012

ADDITIONAL INFORMATION
Languages: English — professional working proficiency; Ukrainian — native; Russian — native
Work Style: Remote-first, distributed and cross-functional teams, Agile / Scrum / Kanban, code review
culture, mentoring of mid-level and junior engineers
Interests: Cycling, hiking, strength and endurance training, embedded electronics, open-source contribution