# IVAN ZAITSEV > Software Engineer Location: Redwood City, California, United States Profile: https://flows.cv/ivanzaitsev1 Software engineer and architect, professional experience since 2005 (15+ years). Generalist with emphasis on backends for high-loaded distributed systems and JVM. Significant experience in ML (python, scala), Big Data (OLAP, [NO]SQL, Map-reduce), Performance (JVM, C++), Web (JS/TS). Excellent skills in problem-solving, communication, work ethics, successful project delivery. Passionate about learning, algorithms, performance optimization, AI, and roguelike video game development. I believe that software industry is first and foremost build by people and for people, and that belief is reflected in how I approach problems. Core Competencies: JVM, Software architecture, Distributed systems, High load, Machine learning, Big Data & OLAP, Functional programming, Concurrency, Algorithms, Data structures, Performance Proficiencies: ------------- Languages: java, scala, kotlin, python, C++, javascript JVM libs: Vertx, Spring, Hibernate, JPA, JDBC, JMS, Servlets, AspectJ, Spark, Hadoop, Quartz, log4j, slf4j, slf4s, ehcache, Jackson, JMX, concurrency, Akka!, scala parsers/combinators, coroutines, jmh Python libs: tensorflow, keras, pytorch, numpy, scipy, pandas, matplotlib, flask Js libs: react, redux, mobx, d3, phaser, immutable-js, lodash, jquery [NO]SQL: Vertica, Clickhouse, PostgreSQL, MySQL, H2, SQLite, MS SQL, Cassandra, Voldemort, Memcached, Redis Messaging: Rabbit MQ, kafka Tools: linters, static analyzers, testing harnesses, profilers, memory analyzers, load testers, CI, containerization, orchestration, etc. Secondary: Golang, Typescript, ASM, PHP, Pascal/Delphi, Basic, Matlab ## Work Experience ### Senior Software Engineer @ RevJet Jan 2015 – Jan 2020 | United States Projects: OLAP backend, ETL, ML recommendation systems, R&D, other internal projects Achievements: — created ML product recommendation pipeline that was crunching terrabytes of raw data and served up to 1k product recommendation requests per second with response time SLA < 20ms — created Recommendation Engine, that managed 100+ user-defined hierarchical models and served up to 1k rps with model response time under 20ms — partially designed and worked on Analytics pipeline, that provided ETL and OLAP capabilities for billions of events per day, with petabytes of historic data and real-time reporting capabilities Technologies: java, scala, kotlin, python, spark, spark ML, vertx, kubernetes, docker, AWS, mysql, vertica, clickhouse, cassandra, kafka, etc. ### Senior Software Engineer @ LifeStreet Corporation Jan 2012 – Jan 2014 • Projects: various projects and services, such as reporting service, inventory management service, playable ads, bidders/optimizers, quota allocation service • Team: at most 3 engineers per project • Key achievements: — redesigned and implemented OLAP backend, with 10x speed for some queries and extendable architecture — created a tech stack from scratch and then successfully lead a team of 3+ people building and delivering Playable ads (a web-based replicas of mobile games) — participated in development and optimization of an ML-based RTB bidder, a high-loaded service with billions of requests per day, reduced RAM requirements 4x • Technologies: scala, tomcat, vertica, clickhouse, memcached, golang, python, scikit-learn, scipy, numpy, javascript, phaserjs, webgl, AWS, kubernetes, docker, etc. • Responsibilities: full-cycle development and support of several internal projects (new features design and implementation, testing, bugfixing, performance testing, refactoring, releasing) ### Software Engineer @ Star Jan 2010 – Jan 2012 • Project: Velti AdServer (world's top Mobile Marketing & Advertising Platform) • Team: 30+ • Achievements: — as a part of a medium-sized team (6-10 software engineers) redesigned ETL pipeline for Ad Server to handle the increased traffic (up to one billion impressions per day) — designed snowflake-like scheme in Postgres, sql-generating backend service, real-time analytics — using extensive knowledge of the whole system was able to fix the most tricky bugs, optimize performance of critical parts, and provide L3 support • Technologies: EJB 3, Spring (DI, Security, AOP, MVC), Hibernate, Hadoop, ehCache, Maven, PostgreSQL, H2, Voldemort, JMS, Flex, Quartz, JAX-WS, AspectJ, JasperReports, JUnit, EasyMock, etc. • Responsibilities: delivering new features (estimation, architecture design, implementation, bug fixing), refactoring, performance optimization, L3 support, interviewing candidates. ### Full stack software engineer @ LLC Prodex Jan 2007 – Jan 2010 • Projects: various websites and web applications • Team: 5+ • Technologies: PHP, Zend Framework, PDO, JavaScript, JQuery, HTML, CSS, Memcached, Lucene, Apache, MySql • Responsibilities: Full cycle of web sites and web applications development. Creating specifications, architecture design, database design, implementing both back- and frontend • Achievements: — Designed and developed a corporate CMS based on Zend Framework — Implemented web-based hotel reservation system for partner company — Created big number of smaller websites for partner companies ### Software/Database engineer @ Computing Center of Donetsk National Technical University Jan 2005 – Jan 2007 | Ukraine • Position: Database engineer, Software engineer • Project: university's internal system for managing students, applicants and staff • Team: 10+ • Technologies: MSSql Server, Delphi 5 • Responsibilities: new features implementation (including complex SQL queries, stored procedures, triggers in addition to Delphi code), legacy code refactoring, support • Achievements: — Successfully released several versions of the project — Implemented trigger-based change history logger — Improved development process in several ways ## Education ### Master's degree in Computer Science Donetsk National technical University ## Contact & Social - LinkedIn: https://linkedin.com/in/aivean - GitHub: https://github.com/Aivean - Portfolio: http://stackoverflow.com/users/1349366/aivean - Portfolio: https://aivean.com --- Source: https://flows.cv/ivanzaitsev1 JSON Resume: https://flows.cv/ivanzaitsev1/resume.json Last updated: 2026-03-29