Святослав

Sviatoslav Valchyshen
Python Developer
vlchshn.code​@gmail.com [open contact info](look above in the "contact info" section) Kyiv, Ukraine / Remote vachyshen_s

PROFILE
Middle Python Developer with 2+ years in production Healthcare B2B. Specialize in FastAPI, async
PostgreSQL, Redis caching, and Celery-based task pipelines. Looking for a backend role with complex
integrations and real performance challenges.

PROFESSIONAL EXPERIENCE
S-PRO 03.2024 – Present | Ukraine, Remote
Python Developer
Project: Healthcare B2B ERP — medical data management and laboratory integration system for a European
clinic network, built on a hybrid architecture (Django-based core and high-throughput FastAPI services).
Team: Agile team of 8 (PM, Tech Lead, 3 Backend, 2 Frontend, 2 QA), 2-week Sprints, Jira.
Tech Stack: Python, FastAPI, Django, DRF, Pydantic, asyncio, SQLAlchemy 2.0, PostgreSQL, Redis, Celery,
WebSockets, Docker, GitHub Actions, Prometheus, Grafana, pytest.
Developed FastAPI endpoints for external medical laboratory integrations, supporting a throughput of
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12,400+ daily requests.
Implemented a multi-level caching strategy using Redis (Cache-aside pattern) for high-frequency analytical
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queries, resulting in a 54% reduction in PostgreSQL CPU usage and decreasing dashboard load times from
4.1s to 620ms.
Leveraged Redis as a message broker for Celery to handle long-running tasks like automated PDF report
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generation and mass notifications, improving API response times under peak load.
Integrated a real-time notification system via WebSockets using stateless JWT authentication to provide
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instant alerts for medical staff, reducing status update latency by 47%.
Wrote unit/​integration tests with pytest, achieving 83% coverage of FastAPI codebase.
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Configured Sentry for runtime error tracking and set up performance monitoring dashboards using
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Prometheus and Grafana.
Implemented Docker multi-stage builds for FastAPI services, reducing final image sizes by 65%. Configured
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CI/​CD pipelines via GitHub Actions and managed local environments with Docker Compose.
Refactored and maintained core Django modules, including doctor scheduling and electronic health records
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(EHR), resolving 64 legacy bugs.
Developed endpoints using Django REST Framework with JWT authentication and RBAC to extend
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administrative panel functionalities for 215 internal users.
Wrote pytest tests for core Django modules, increasing code coverage from 41% to 76%.
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SKILLS
Backend: Python, FastAPI, Django, DRF, asyncio, Pydantic, Celery, WebSockets, JWT/OAuth2, pytest
Databases: PostgreSQL, Redis, SQLAlchemy 2.0 (async), Alembic
DevOps: Docker, Docker Compose, GitHub Actions
Tooling: Poetry, Ruff, Git, Linux
Monitoring: Sentry, Prometheus, Grafana
Process: Agile, Scrum, Jira

EDUCATION
Bachelor of Computer Engineering
Faculty of Applied Mathematics (FAM)
National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute"

LANGUAGES
Ukrainian
Native speaker (C2)

English
Intermediate (B2) — Strong technical reading & documentation skills