Pavlo Herasymchuk

Pavlo Herasymchuk

Full-stack engineer building real-time and distributed systems, from high-load ASP.NET Core APIs and PostgreSQL tuning to Vue and React interfaces. MSc Computer Science student at EPFL.

Open to a summer or autumn 2027 internship, or a 6-month master's thesis in industry from September 2027. Based in Lausanne with Swiss Permit S, so no visa sponsorship is needed.

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Experience

Full-stack software engineer, Linkos Group

Jul 2025 – May 2026

Cashalot: a cloud cash register used by tens of thousands of Ukrainian businesses to register receipts with the State Tax Service. Kyiv.

  • Designed and scaled ASP.NET Core APIs for the web cabinet and POS clients, sustaining hundreds of requests per second at peak.
  • Cut latency of high-traffic operations by over 40% by restructuring PostgreSQL queries and indexes, measured before and after.
  • Built a RabbitMQ and Hangfire pipeline for large Excel exports that processes hundreds of thousands of operations a day, with live progress over WebSockets.
  • Delivered real-time notifications over SignalR to 10k–50k daily users, and designed transactional flows that keep concurrent financial operations consistent.
  • Owned the dashboard and settings sections of the Vue 3 and TypeScript web cabinet, and shipped two-factor authentication and fine-grained role-based access end to end.

C#, ASP.NET Core, SignalR, Dapper, PostgreSQL, Hangfire, RabbitMQ, Vue 3, TypeScript, Pinia, Docker, GitLab CI

Trainee software engineer (.NET), EPAM Systems

Feb 2025 – Jul 2025

Online game store platform: catalogue, accounts, orders and payments. Kyiv.

  • Implemented a multi-module REST API with Clean Architecture, DDD and CQRS, including payments through an external microservice and JWT role-based authorization.
  • Built GitLab CI/CD pipelines deploying to Microsoft Azure, and covered business logic with xUnit tests.

C#, ASP.NET Core, EF Core, SQL Server, Angular, Azure, GitLab CI/CD

Projects

CycleShare

My bachelor's thesis, graded 100/100. Designed, built and deployed on my own.

A bicycle rental platform where owners list bikes, renters book and pay, and the owner follows each ride live on a map.

Open cycleshare.space
CycleShare architecture A React single-page app and a GPS tracker connect to a Docker Compose deployment. Nginx routes traffic to four ASP.NET Core microservices, each with its own PostgreSQL database. GPS positions flow from the tracker through a Traccar server and the tracking service, then over SignalR to a live map in the browser. Payments go to Stripe. Docker Compose, 11 containers 4 ASP.NET Core microservices, CQRS with MediatR cycleshare.space Distance Duration Avg speed React 19 SPA MUI, Leaflet, SignalR client GPS tracker On the bike, IMEI-registered Nginx TLS, routing, WebSockets Marketplace & bookings Listings, bookings, reviews PostgreSQL Chat SignalR hub, read receipts PostgreSQL Tracking Traccar listener, SignalR PostgreSQL Tracker shop Orders, IMEI registration PostgreSQL Traccar server Device protocols, WebSocket feed Stripe Checkout Payments, webhooks Legend Live GPS position HTTPS request Container boundary Built with .NET 8 EF Core MediatR SignalR PostgreSQL 16 Stripe Traccar React 19 Leaflet Docker Nginx xUnit

Scroll sideways to see the whole diagram.

  • Four microservicesMarketplace and bookings, chat, tracking and a tracker shop, each with its own PostgreSQL database
  • Live GPS trackingPositions from a self-hosted Traccar server pushed to the map over SignalR, with route replay and trip stats
  • Real-time chatSignalR groups per conversation, read receipts and typing indicators
  • PaymentsStripe Checkout confirmed by webhooks, plus a tracker shop with its own order service
  • Production deployment11 Docker Compose containers behind Nginx with auto-renewed Let's Encrypt TLS
  • 480+ automated tests70–83% coverage per service, SonarQube A ratings, 250+ requests/s under JMeter load

Peer-to-peer gossip system

EPFL, Decentralized Systems Engineering, autumn 2026. Go.

A fully decentralized system built over four assignments: UDP networking and routing, rumor-mongering gossip with anti-entropy, chunked content-addressed file sharing, and multi-Paxos consensus recorded on a replicated blockchain.

The figure shows push gossip: each round, every informed peer tells one random neighbour. Grey messages reach peers that already knew.

A message spreading through a network of 14 peers by gossip
Waiting to start
test build scan

Hive emulator: CI/CD and Kubernetes

KPI, 2025. .NET 8, React, Redis

Two .NET 8 APIs, Redis and a React map, shipped by a GitHub Actions pipeline: 31 tests, CodeQL scanning, SHA-tagged images and rolling deployments to Kubernetes, monitored with Prometheus and Datadog.

Code

STM32Cortex-M3 OPEN CLOSED ALARM

Bare-metal STM32 firmware

KPI, 2026. C, Cortex-M3

A car alarm and a fan controller written straight against the registers, with no HAL: interrupt-driven state machines, hardware timers, ADC, PWM and a UART command interface.

Code

WebGL2 shadow mapping

KPI, 2025. JavaScript, GLSL

Two-pass shadow mapping, per-fragment Phong lighting and 3D fundamentals in raw WebGL2, written without libraries and running live in the browser.

Live demo Code

Recursive view 335 ms Materialized view 81 ms Query with dead tuples / after VACUUM 10.5 → 7.4 ms

Query optimization: PostgreSQL and Oracle

KPI, 2026. SQL, Docker

Execution plans for every scan type, planner hints, MVCC and VACUUM measurements, and materialized views that cut a recursive query from 335 ms to 81 ms.

Code

Parallel Bellman–Ford

KPI, 2025. Java

Shortest paths on a thread pool, with edges partitioned by destination so threads never write the same vertex. 1.7–2.5× speedup on 4 cores.

Code

Parallel computing in Java and MPI

KPI, 2025. Java, C++

Striped and Fox block matrix multiplication on threads and ForkJoin, plus blocking, non-blocking and collective MPI versions verified against the sequential result.

Code

Algorithms design in C++

KPI, 2023

Six projects from scratch: a genetic algorithm and ant colony optimization for TSP, A* vs iterative deepening maze search, external merge sort, an AVL-tree store and an expectimax game AI.

Code

RoadVision-IoT

KPI, 2026. Team of six. Python

Road-quality and bus-occupancy monitoring over MQTT, with edge classification, Redis batching and a FastAPI store streaming to a live map. I built the bus-occupancy feature end to end and the hub-to-store integration.

Code

Computer vision with OpenCV

KPI, 2024. Python

Vehicle detection in aerial video, SIFT and FLANN feature matching, CNN-feature clustering, object tracking and stereo 3D reconstruction.

Code

Cyberbullying classification

KPI, 2024. Python

15 model and feature combinations on about 48k tweets. Best result: 86% accuracy and 0.86 weighted F1.

Code

MazeSolver

KPI, 2023. C++17

Dijkstra and A* over a hand-written binary heap. A* expands about 10× fewer cells in open mazes with identical paths.

Code

image-editor

KPI, 2023. C++17

A dependency-free 24-bit BMP decoder and encoder with nearest-neighbour and bilinear scaling.

Code

URL24

Personal, 2025

A URL shortener with an ASP.NET Core API and a React client, optimized for minimal redirect latency.

Visit

More on GitHub: machine learning notebooks, discrete-event simulation, Android apps (media player, sensor toolkit), a Spring Boot booking app, Strassen multiplication and x86 assembly.

Education

MSc Computer Science, EPFL

Sep 2026 – Feb 2028

Lausanne. Decentralized Systems Engineering, Advanced Networks, Mobile Networks, Experience Design.

BSc Software Engineering, Igor Sikorsky Kyiv Polytechnic Institute

Sep 2022 – Jun 2026

GPA 98.38/100, top 2% of cohort, diploma with honours, bachelor's thesis graded 100/100.

Skills

Languages
C#, TypeScript, JavaScript, C/C++, Java, Python, Go, Kotlin, SQL
Backend
ASP.NET Core, SignalR, EF Core, Dapper, MediatR, Hangfire, RabbitMQ, REST, WebSockets
Frontend
Vue 3, Pinia, React 19, MUI, Angular, Leaflet, Vite
Data
PostgreSQL, Oracle, SQL Server, Redis, pandas, scikit-learn, Keras
Infrastructure
Docker, Kubernetes, GitHub Actions, GitLab CI/CD, Azure, DigitalOcean, Nginx, Prometheus, Linux
Embedded & graphics
STM32 bare-metal C, MQTT, WebGL2, GLSL, OpenCV
Spoken
Ukrainian (native), English (C1), French (A1, learning)

Write to me at pgerasymchuk@gmail.com

LinkedIn GitHub