Sergey Vasilyev

  • Email: (preferred).
  • Phone: +49 157 3232 0684.
  • Location: Berlin, Germany.
  • Work permit: NE (Niederlassungserlaubnis, Germany).


A skilled developer with ~20 years of experience. Master of Computer Sciences majored in Distributed Computer Systems. Author of Kopf, a Kubernetes OPerators (Pythonic) Framework: Talks:

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


Senior Backend Engineer in Pricing & Forecasting
Zalando SE

One of the biggest European e-commerces and a fashion platform; ~15000 employees.
Feb 2018 – now. 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, solved the data gravity problem.

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

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

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

Developing an ecosystem (frameworks, toolkits, CLIs/UIs, infrastructure, guidelines, documentation, etc) for integration- & performance- & endurance- & stress-testing of a cloud (IaaS). Leading a team of 3 Python developers, plus a group of QA engineers in order to utilize the developed toolkits and to achieve a higher level of QA automation.

Senior Software Engineer in QA Automation/Infrastructure

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

Maintaining and improving the infrastructure and the tools for the QA automation team.


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

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

With the IT team:

Reworked the whole infrastructure, 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 the 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

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

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. Python, PHP, Oracle PL/SQL.

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

Senior Python Developer

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

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

Python Developer

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

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.

Senior PHP Developer
Project 2000+

SaaS web site & application constructor (startup); 5 employees.
July 2008 – May 2009 (11 months). Moscow, Russian Federation.

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

PHP Web Developer
Howard Design Studio

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

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

PHP Web Developer

August 2005 – August 2007 (2 years).

Developed my own Content Management System (CMS), used in a few web-sites.


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

Bachelor’s Degree, Computer Science
Siberian State Technological University