🇱🇹 Vilnius, Lithuania • Fintech & High-Load Systems

Aistis Marčiauskas

Senior Backend Engineer

PHP • Python • Scalable Architectures

10+ yrs

backend experience

40%

latency reduction

35%

efficiency gain

Senior Backend Engineer with 10+ years of experience building scalable backend systems for fintech and high-traffic platforms. Strong expertise in PHP and Python, database performance tuning, and service-oriented architectures. Proven track record of modernizing legacy systems, improving performance under heavy load, and delivering automation that increases engineering speed and business impact.

Selected Impact

Reduced p95 latency by 40% in data-intensive loan scoring workflows through MySQL query optimization, execution plan analysis, and targeted caching.
Increased feature delivery speed by 30% by decomposing tightly coupled legacy modules into domain-aligned services.
Reduced harmful bot and scraper traffic by 20% at HomeToGo by building a real-time hybrid detection system combining heuristics and machine learning.
Improved engineering efficiency by 35% by introducing AI-assisted workflows for code generation, automated testing, and CI/CD automation.

Education

B.Sc. in Information Technology
Vilnius University — 2009 – 2015
Relevant coursework: Distributed Systems, Database Design, Algorithms

Professional Experience

Senior Backend Engineer

BnP Finance — Vilnius, Lithuania / Remote • Apr 2025 – Present

Architect and develop backend services for automated loan issuance and end-to-end customer lifecycle management in a regulated fintech environment.
Led the refactoring of a monolithic loan-processing engine into loosely coupled, domain-aligned services, improving maintainability, auditability, and parallel delivery across teams.
Optimized MySQL-heavy reporting and risk assessment workloads, improving processing efficiency by 25% under high concurrency.
Designed resilient, state-driven workflows for critical financial operations, improving reliability and compliance readiness.
Tech: PHP 8.3, Symfony, Laravel, MySQL, RabbitMQ, REST APIs

Freelance Senior Backend Engineer

MB TapTechTap • Jan 2023 – Present

Designed and delivered API-first backend systems for SMEs with a focus on scalability, cloud-native deployment, and third-party integrations.
Reduced infrastructure costs by 20% through containerization, AWS resource right-sizing, and database optimization.
Built AI-assisted code generation and testing workflows that reduced MVP delivery time from weeks to days.
Implemented high-performance integrations using PHP, Python, Redis, and AWS services including S3 and Lambda.
Tech: PHP, Python, Docker, Redis, AWS, FastAPI, Flask

Software Engineer

HomeToGo • Jan 2019 – Dec 2022

Led backend development for the Traffic Quality initiative, building real-time systems to detect and mitigate scraper and bot traffic at scale.
Developed a hybrid detection engine combining rule-based heuristics and machine learning models with Scikit-learn, improving crawler identification accuracy by 25%.
Partnered with infrastructure teams on edge-level mitigation strategies, reducing origin server load by 20% and protecting core services from abusive traffic.
Built and maintained high-scale backend services and internal tooling in PHP and Python.
Tech: PHP, Python, Scikit-learn, Redis, Aerospike, AWS, Jenkins

Web Developer

Orakulas Services • Nov 2016 – Dec 2018

Designed and implemented international registration and KYC workflows integrating multiple third-party identity verification providers.
Automated back-office processes, reducing manual operational effort by 35%.
Improved reliability and auditability of high-volume transaction logging and internal operational workflows.
Tech: PHP, PostgreSQL, SOAP, REST APIs

Earlier Experience

nSoft and SS Solutions

Additional engineering roles at nSoft and SS Solutions. Details available on LinkedIn or upon request.