Vitaliy

Vitaliy Kuzmich
Senior Python Engineer | Django · DRF · FastAPI · Full-Stack
[open contact info](look above in the "contact info" section)• [open contact info](look above in the "contact info" section) • github.com/vitaliy-kuzmich

1,500× faster critical path · Release cycle: 2 months → 1 day · 20+ integrations unified · 12
years of backend delivery

PROFESSIONAL SUMMARY
Senior Python engineer, twelve years of backend work across fintech, e-commerce, healthcare and enterprise
operations. Roughly half of it spent rescuing systems that had grown slow or unmaintainable, the other half
building new ones against a deadline.
Takes a problem from the first stakeholder conversation through to a running service: data model, API,
background workers, the front-end where it is needed, deployment, then a handover the client's team can
actually work from. Has been the only senior engineer on a project and has also worked inside teams with
strict review standards.

SELECTED ACHIEVEMENTS & IMPACT
 Made a critical processing path roughly 1,500× faster using caching, a denormalised data model and
asynchronous workers. The server capacity purchase planned for that problem was cancelled.
 Cut the release cycle from two months to one day, replacing a manual process with containerised CI/CD
and an automated test suite.
 Brought reporting screens down from minutes to near-instant by rewriting the queries, indexes and ORM
access patterns behind them. Business users went back to using tools they had been avoiding.
 Delivered a greenfield SaaS product from empty repository to production in under three months, which
pulled the client's revenue forward by a quarter.
 Reduced partner onboarding from weeks to days by consolidating 20+ external service integrations into a
single concurrency-safe layer.
 Refactored a legacy platform under live traffic, with no planned downtime and no interruption for active
users, while it was still accumulating incidents faster than fixes.
 Introduced tests, static typing and code review on teams that had none. Regressions dropped and every
engineer who joined afterwards ramped up faster.

TECHNICAL SKILLS
Languages: Python 3.x, SQL, TypeScript (TS), JavaScript (ECMAScript, ES6+ / ES2023), Bash
Frameworks: Django 4 / 5, Django REST Framework (DRF), Django ORM, Django Channels, Django Admin
customisation, FastAPI, Flask, Starlette, Celery, Celery Beat, SQLAlchemy, Alembic, Pydantic v2, asyncio,
aiohttp, httpx, Gunicorn, Uvicorn, WSGI / ASGI
Ecosystem & Tooling: pytest, pytest-django, factory_boy, Coverage.py, mypy, Ruff, Black, isort, Poetry, pre-
commit, Sentry, structlog, drf-spectacular / OpenAPI, django-filter, django-allauth, Simple JWT, Pandas, NumPy,
Scrapy, boto3
Architecture: Microservices, RESTful API design, GraphQL, gRPC, event-driven architecture, Domain-Driven
Design (DDD), CQRS, clean architecture, SOLID, background job processing, WebSockets, real-time systems,
high-load and low-latency design, legacy modernisation
Data & Messaging: PostgreSQL, MySQL, ClickHouse, MongoDB, Redis, Elasticsearch, Apache Kafka,
RabbitMQ, schema design, indexing, query optimisation, migrations, caching strategies
Front-End: JavaScript (ECMAScript ES6+), TypeScript, React.js (Hooks, Context, Redux Toolkit), Angular
(Angular 2+, RxJS) and AngularJS, Vue.js, HTML5, CSS3, SASS, Bootstrap, Jinja2 and Django templates,
responsive design, single-page applications (SPA), Jest
DevOps & Cloud: Docker, Docker Compose, Kubernetes (K8s), Jenkins, GitLab CI/CD, GitHub Actions, AWS
(EC2, S3, RDS), Nginx, Gunicorn deployment, GNU/Linux administration, Git, Prometheus and Grafana
Security: OAuth 2.0, JWT, SAML 2.0 single sign-on, token and session authentication, RBAC, OWASP-aware
secure coding
Also works with: Java and Spring, Go, Node.js and TypeScript on adjacent services
PROFESSIONAL EXPERIENCE

Senior Backend Engineer (Python) — Purchase Order Management Platform
Confidential Client (NDA) · Enterprise Procurement | 10.2023 – 12.2024
 Delivered new domain functionality across a procurement platform: REST API endpoints, service-layer
business rules, relational data model changes and the JavaScript/TypeScript front-end that consumed
them.
 Introduced automated tests and stricter validation around order workflows, reducing the volume of
production defects reported by business users.
 Worked directly with stakeholders to convert business requirements into technical specifications and
incremental, reviewable releases.

Senior Backend Engineer — Checkout & Identity Verification System
Confidential Client (NDA) · Retail Technology | 01.2022 – 08.2022
 Built a biometric (fingerprint) authentication module for a retail checkout product: device integration layer,
verification API and operator-facing UI.
 Implemented token-based authentication and fine-grained permission handling to protect sensitive
checkout operations.
 Owned deployment, on-site troubleshooting and handover documentation for the client's internal team.

Senior Backend Engineer — Feedback SaaS Platform (Greenfield)
Confidential Client (NDA) · SaaS Product | 09.2021 – 11.2021
 Designed and built a customer-feedback service from a blank repository: domain model, REST API contract,
database schema, background processing and deployment pipeline.
 Selected the architecture and toolchain, then delivered a production-ready MVP inside a fixed, aggressive
deadline.

Senior Backend Engineer — Fleet Management System
Confidential Client (NDA) · Logistics & Transportation | 07.2021 – 01.2022
 Modernised and supported a large legacy fleet-management platform, refactoring critical modules while
preserving uninterrupted service for active operators.
 Debugged production issues involving concurrency, data consistency and third-party telematics
integrations.
 Delivered both API-side fixes and front-end improvements as the sole full-stack owner of the module.

Senior Engineer — Healthcare ERP & Cloud Analytics (ClickHouse)
Confidential Client (NDA) · Healthcare & Cloud | 09.2020 – 04.2021
 Implemented new modules and resolved defects in a production healthcare ERP processing sensitive
patient and billing data.
 Built a cloud analytics service on top of ClickHouse for high-volume reporting workloads.
 Tuned SQL queries, indexes and ORM access patterns to significantly speed up the heaviest reporting
screens.

Senior Full-Stack Engineer / DevOps — Developer Tooling Platform
Confidential Client (NDA) · Atlassian Ecosystem | 12.2019 – 06.2021
 Built core components of a Jira extension from scratch, integrating the platform API with internal enterprise
services.
 Owned CI/CD and infrastructure: Docker images, Jenkins pipelines, environment provisioning and
automated releases.
 Served as the messaging / queueing subject-matter expert on a parallel engagement, tuning broker-based
integration flows for throughput and delivery guarantees.

Software Architect & Lead Backend Developer — High-Load Exchange Platform
Confidential Client (NDA) · FinTech / Trading | 03.2018 – 06.2018
 Designed the microservice architecture of a high-load cryptocurrency exchange: service decomposition,
order processing pipeline, denormalised storage model, Redis caching and asynchronous messaging
backbone.
 Defined scalability, fault-isolation and data-consistency strategies for concurrent trading workloads.
 Guided the development team technically and reviewed critical concurrency-sensitive code paths.

Senior Engineer & Consultant — Identity, E-Commerce and Blockchain Integrations
Confidential Clients (NDA) · Multiple Industries | 12.2017 – 03.2019
  Implemented federated single sign-on with multi-provider SAML 2.0 support for an enterprise security
stack.
 Delivered backend features and complex analytical SQL reporting for an e-commerce platform.
 Advised clients on integration architecture and technical feasibility, then built the backend services that
followed from it.

Full-Stack Engineer & Linux Administrator — Integration Library, Risk Platform, ERP
Confidential Clients (NDA) · Enterprise & FinTech | 01.2015 – 05.2017
 Architected a concurrent integration library that served as the connectivity core between a large enterprise
platform and 20+ external services and protocols.
 Built PRIIPs, a clustered web application computing financial risk metrics, owning computation engine, API
and UI.
 Delivered a childcare ERP platform from scratch and operated its production Linux stack (Nginx, application
servers, mail, DNS, FTP).

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

OPEN-SOURCE & PERSONAL ENGINEERING PROJECTS
Self-hosted cloud storage server — Author of an open-source Nextcloud alternative built to run on low-
resource hardware: file storage, sharing, authentication and HTTP API, with a JavaScript SPA front-end.
Open-source trading platform — Microservice architecture with Redis caching and a denormalised data
model, published on GitHub.
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