YD

A little bit about me... 

Biography

Hi, I'm Yasen, a backend engineer based in Sofia. I build large-scale, service-oriented systems and own features end-to-end: from architecture and API design through CI/CD, infrastructure, and production support.

I keep full ownership of code quality, security, and architecture. I start from the problem and choose technology based on constraints, and I like explaining the trade-offs behind a decision as much as making it.

My production experience spans Python microservices, REST and GraphQL APIs, containerized AWS workers, and billion-row data platforms, with a strong focus on performance, secure coding, and input validation. I'm currently deepening in Rust and C for systems and performance-critical work.

Yasen
0+

projects completed

0+

years of experience

Skills

Languages at the core, APIs and data in the middle, platform and tooling on the outer ring.

Backend& Systems
Python
Rust
C
TypeScript
REST APIs
GraphQL
FastAPI
SQL
React
PHP
Docker
Linux
AWS
Terraform
CI/CD
Claude Code

Experience

  • Software Engineer @DataArt

    2026-Present | Sofia, Bulgaria
    • Build and maintain FastAPI/SQLAlchemy microservices and containerized SQS-fed AWS Lambdas for a royalty accounting platform processing billions of revenue rows, exposed to a React frontend through REST and a GraphQL aggregation layer.
    • Own delivery end-to-end via Jenkins CI/CD (Dockerized lint, type, and unit stages, real-container Lambda integration tests per PR, blocking vulnerability scanning) and Terraform infrastructure with Checkov and AI review gates; remediated CVEs and right-sized Lambdas from measured memory peaks.
    • Profiled and resolved Lambda performance issues end-to-end, using CloudWatch and Snowflake query history to disprove assumed bottlenecks before changing code, then cut peak memory by ~50% with vectorized PyArrow processing and streaming zip output to S3.
    • Develop secure service-to-service APIs with JWT auth middleware, Auth0 M2M tokens backed by AWS Secrets Manager, YAML-driven access rules, Pydantic request validation, and per-request correlation IDs traced through Datadog APM and Sentry.

  • Backend / Full-Stack Software Developer @MClimate

    2024-2025 | Sofia, Bulgaria
    • Designed and implemented a Python rules engine evaluating real-time IoT device events (LoRaWAN telemetry) to trigger automations, powering 500+ active rules in production.
    • Led Meilisearch integration and backend microservice refactors (PHP API, NestJS), deploying a dedicated search service in Docker Swarm and achieving a 10x improvement in search performance.
    • Led a JavaScript-to-TypeScript migration and introduced CI quality gates (pre-commit hooks, commit standards), cutting type-related production defects.

  • Technical Consultant @FactSet

    2022-2024 | Sofia, Bulgaria
    • Wrote and optimized complex SQL over large-scale financial datasets, cutting query times for data deliveries.
    • Built and maintained ETL workflows delivering financial data to clients, with a focus on data correctness.

Education

  • Full Stack Open 

    2023-2023 | University of Helsinki

    Full stack web development course focusing on development with React, Redux, Node.js, PostgreSQL and MongoDB. More advanced topics include GraphQL, TypeScript, Docker, and end-to-end testing.

  • Master in International Business Law 

    2014-2015 | University of Catolica

    Master in International Business Law with a focus on finance.

  • Bachelor of Law 

    2010-2013 | University of Manchester

    Bachelor of Law, focusing on common law.