Sergey Vasilyev

CAREER HIGHLIGHTS

Keywords: Backend, Python, Pytest, Postgres, ClickHouse, DevOps, Kubernetes, Docker, AWS, SaaS, PaaS, IaaS, Cloud, etc.

A skilled Software Engineer with 25+ years of experience. Master of Computer Sciences majored in Distributed Computer Systems. Author of Kopf, a Kubernetes Operators Framework for Python: https://github.com/nolar/kopf (2.5k⭐️), and a few smaller open-source libraries: looptime, kmock, setup-k3d-k3s. Gave talks on developing Kubernetes operators in Python and presenting Kopf at KubeCon San Diego 2019 and RedHat DevNation Day 2020.

EXPERIENCE

Senior Software Engineer
Datafold, Inc.

Data reliability platform; a seed-stage/series-A startup with ≈20+ employees.
Oct 2021–Mar 2025. Worldwide-remote (from Berlin, Germany).

Developed and maintained the whole spectrum of the backend services in the app: from the API (FastAPI) to background jobs covering such subsystems as time series of custom metrics, simplistic anomaly detection and alerting, data diffing and profiling, AI/LLM for pipeline translations (SQL & non-SQL dialects), column-level lineage graph, GitHub/GitLab/Slack integrations, enterprise authentication (SSO, SAML, OAuth2, etc.), and so on — everything necessary for customer satisfaction and ensuring the reliability of the customers' data.

Python, FastAPI, Celery, Postgres, ClickHouse, Neo4j, LLM, AI.

Senior Backend Engineer in Pricing & Forecasting
Zalando SE

One of the biggest European e-commerces and a fashion platform; ~15000 employees.
Feb 2018–Sep 2021. Berlin, Germany.

Maintained & refactored a Machine Learning platform for article sales & demand forecasting. Migrated the data processing and sales forecasting pipelines from raw AWS+STUPS to Kubernetes, and solved the data gravity problem.

Mentored junior and middle Software Engineers and advised the Data Scientists on best software development practices, CI/CD workflows, software architectures, tips and tricks.

Python, AWS, Kubernetes, Machine Learning.

Senior Python Developer / TeamLead Integration
ProfitBricks GmbH (renamed to Ionos SE)

Cloud computing IaaS company; 100+ employees.
Sep 2015–Jan 2018. Berlin, Germany.

Developed an ecosystem (frameworks, toolkits, CLIs/UIs, infrastructure, guidelines, documentation, etc) for integration- & performance- & endurance- & stress-testing of a cloud (IaaS). Led a team of 3 Python developers, plus a group of QA engineers.

Python, self-made cloud platform.

Senior Software Engineer in QA Infrastructure
Acronis

International backup solution provider; 700+ employees.
Nov 2014–Aug 2015. Moscow, Russia.

Maintained and improved the infrastructure and the tools for the QA automation team.

Python.

CTO
gdeetotdom.ru

Real estate web portal and aggregator; 80 employees.
July 2012–February 2014 (1 year 8 months). Moscow, Russia.

The same as for the Head of Development below, plus the IT department.

With the IT team:

Reworked the whole infrastructure, and virtualized everything with no harm to the system. Moved most of the infrastructure from ancient collocated bare-metal servers to rented modern servers (including the refactoring of the infrastructure so that it becomes possible). Reduced the monthly hosting bill by approximately 40-50% and long-term TCO by 50-70%. Built technical support for partners and for employees.

With development teams:

Continued all the things regarding the software development (see below for Head of Development): system design, infrastructure and platform services, control of the development process, etc.

Head of Development
gdeetotdom.ru

Real estate web portal and aggregator; 80 employees.
August 2010–July 2012 (2 years). Moscow, Russia.

Managed a department of front-end, back-end, database developers, and QA specialists. Expanded from 13 employees to 27 employees in 6 months. Built the processes to work and effectively communicate within a distributed team of web developers with 80% spread across the country.

Led a redesign to a three-tier service-oriented architecture (SOA; now known as "microservices")—for scalability and maintainability—while keeping the existing systems up and running.

Directly managed some of the company's long-term projects: mobile applications, back-office import/export/crawling systems, intranet content management, and infrastructure.

Python, PHP, MySQL, Oracle PL/SQL.

Senior Python Developer
gdeetotdom.ru

Real estate web portal and aggregator; 50 employees.
February 2010–August 2010 (7 months). Moscow, Russia.

Led a team of three Python developers: task management and prioritization, features and milestones planning, control of deadlines, mentoring, and advising for architectural solutions.

Python, Django, MySQL.

Python Developer
gdeetotdom.ru

Real estate web portal and aggregator; 50 employees.
September 2009–February 2010 (6 months). Moscow, Russia.

Designed from scratch a back-office system for automated data mining of third-party real estate data sources to the company's web portal.

Python, Django, MySQL.

Senior PHP Developer
Project 2000+

SaaS website & application constructor (startup); 5 employees.
July 2008–May 2009 (11 months). Moscow, Russia.

Developed a dating app. Mostly the backend: databases, ORM, caching, performance, scaling.

PHP.

PHP Web Developer
Howard Design Studio

Web design and web development agency; 7 employees.
August 2007–July 2008 (1 year). Moscow, Russia.

Developed studio's content management system (CMS), and universal content-handling tools (typographic and similar). Built server and client sides of multiple websites.

PHP, MySQL.

PHP Web Developer / Self-employed

August 2005–August 2007 (2 years).

Developed websites and Adobe Flash applications for various clients.

PHP, Adobe Flash.

EDUCATION

Master's Degree, Computer Science
Majored in Distributed Automated Systems.
Siberian State Technological University