Василь

Vasyl Tysianchyn
Senior Backend Engineer

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Location - Slovakia Email: [open contact info](look above in the "contact info" section)​
Years of experience - 5+ years Phone: [open contact info](look above in the "contact info" section)​
Main stack - JavaScript, TypeScript, Node.js LinkedIn: [open contact info](look above in the "contact info" section)

Summary

JavaScript Back-End Engineer with 5+ years of experience. Successfully delivered multiple
projects to production. Focused on scalable architectures, responsible, and quick to learn

Technical skills

●​ JavaScript ●​ Google Cloud Platform
●​ TypeScript ●​ Amazon Web Services
●​ Node.js ●​ Microsoft Azure
●​ Nest ●​ Heroku
●​ Express ●​ CI/CD
●​ Redis ●​ Git
●​ SQL ●​ 3rd party API
●​ MongoDB ●​ REST API
●​ RabbitMQ ●​ Microservices
●​ gRPC ●​ Serverless

Education

●​ Uzhhorod National University​ ●​ Uzhhorod National University
Bachelor's in Software Engineering Master's in Software Engineering
(2019-2021)​ (2021-2023)
 Professional Experience

Back-End Developer, Zazmic
June 2019 - Present

Job Title: Backend Engineer
Project: AI-Powered Healthcare Application (November 2024 - January 2025)
Responsibilities:

●​ Implemented backend solutions, improving system response time by 30% and reducing
downtime by 25%.
●​ Expanded test coverage from 70% to 95%, enhancing system stability and performance
monitoring.
●​ Developed approved architectural improvements, reducing system failures by 40%.
●​ Reduced critical system failures by 40% and increased customer retention rate by 15%
through platform stabilization and feature expansion.

Tech Stack / Tools: TypeScript, Nest, RabbitMQ, Redis, Postgres, Twilio, Swagger, Jest, Cron
schedulers, microservice architecture.

Job Title: Backend Engineer
Project: Medical Image Viewer (August 2024 - November 2024)
Responsibilities:

●​ Seamlessly integrated a viewer tool into the main BE platform, improving system
performance by 30% and ensuring 99% system uptime and logic integrity.
●​ Secured daily user connections and implemented robust authorization mechanisms,
reducing security vulnerabilities by 40%.
●​ Created over 150 unit tests to ensure the stability and reliability of the project.
●​ Optimized transmitting secured DICOM images by 40%.

Tech Stack / Tools: MongoDB, Postgres, Nest, Koa, TypeScript, Redis, microservices.

Job Title: Backend Engineer
Project: AI Diagnostics Platform (February 2024 - August 2024)
Responsibilities:

●​ Led the deployment of a healthcare platform across 3 cloud environments, reducing setup
time by 50%.
●​ Stabilized the platform, increasing system reliability by 90% and reducing downtime.
●​ Designed integration with 3+ AI API services to meet business needs and requirements.
●​ Constructed a scalable microservices architecture to handle over 1 million records of
medical data efficiently.

Tech Stack / Tools: Node.js, TypeScript, Koa, RESTful API, Redis, microservices
Job Title: Backend Developer​
Project: Cloud-Based Medical Workflow System (March 2020 - February 2024)

Responsibilities:

●​ Ensured 99.9% uptime for medical workflow systems, processing imaging data with
AI-driven optimizations.
●​ Developed integrations for handling DICOM and HL7 data for medical imaging and
diagnostics.
●​ Upgraded cloud-based infrastructure, reducing latency by 35% and cutting operational
costs by 20%.
●​ Collaborated on implementing machine learning tagging, reducing the time by over 30%,
and increasing the accuracy of radiological assessments by 15%.
●​ Improved platform reliability for critical medical workflows, reducing processing time
for stroke diagnostics by 40%.

Tech Stack / Tools: JavaScript, TypeScript, Node.js, Nest, Express, Koa, Redis, PubSub, Jest,
Swagger, MongoDB, Postgres, Cron-Schedulers, Cloud-Functions/Lambda, Microservice
architecture

Job Title: Backend Developer​
Project: IAM System (December 2019 - March 2020)
Responsibilities:

●​ Created end-to-end (e2e) tests to ensure robust coverage (over 95%) for authentication
and access control features.
●​ Increased test coverage by 60%, reducing the risk of authentication failures in production.

Tech Stack / Tools: Node.js, OAuth, Puppeter, Postman

Job Title: Backend Developer​
Work Period:
Project: Social Media Management Platform (June 2019 - December 2019)

Responsibilities:

●​ Built backend features that helped influencers automate 80% of their social media tasks,
boosting engagement rates by 25%.
●​ Boosted posting efficiency by 35% by optimizing workflows and integrating scheduling
tools.
●​ Built functionality to detect the best time for publishing posts based on engagement by
55% by leveraging real-time data and trends.

Tech Stack / Tools: JavaScript, Node.js, Express, Google Authenticator, social networks API
Back-end Developer, Rocketech Software Development
April 2019 - June 2019

Responsibilities:
●​ Engineered and introduced application-level transaction management for MongoDB,
improved transaction reliability for 100.000+ operations per day before native transaction
support (pre-4.0).
●​ Integrated MongoDB with message broker RabbitMQ for distributed transaction
orchestration, enabling seamless handling of over 50.000 transactions per day.

Back-end Developer / Dev-Ops, Foxtrapp Limited
March 2017 - April 2019

Responsibilities:
●​ Maintained back-end components for high-load projects for over 5+ projects..
●​ Administered cloud infrastructure with AWS and Heroku, ensuring high availability for
over 10 projects.
●​ Engineered CI/CD pipelines, and automated deployments for 10+ projects.
●​ Monitored server-side performance, improving project efficiency by 30%.
●​ Reduced deployment time by 50% and errors through advanced CI/CD strategies.
●​ Boosted productivity by 25% with innovative scheduling tools.
●​ Enhanced data analysis processes, achieving a 30% improvement in reporting accuracy
and insights.