Sergey Trofimov, Software Engineer, Berlin

[ linkedin.com/in/sarg | github.com/sarg | de.strofimov@gmail.com ]

Objective

To obtain a challenging and impactful software engineering role leveraging my expertise in building scalable backend systems and leading development teams.

Summary

A seasoned software engineer with 15+ years of experience building and maintaining scalable distributed backend applications. Proficient in Java, Kotlin, and Python, with a strong focus on coding best practices, comprehensive documentation, and robust deployment/monitoring strategies. Proven ability to refactor/optimize applications, mentor teams, and leverage DevOps practices in Linux environments. Passionate about clean code, collaboration, and continuous learning.

Skills

• Languages: Java, Kotlin, Python, Perl, Clojure
• Databases: Postgresql, MySQL, Redis, ClickHouse, ElasticSearch, MongoDB
• GCP: Compute Engine, Kubernetes, Cloud Storage, Load Balancers, VPN/Partner Interconnect
• AWS: EC2, RDS, S3, Lambda
• DevOps: Linux, Ansible, Puppet, Terraform, Jenkins, TeamCity, Zabbix, Grafana, Docker, CI/CD
• Backend: Guice, jOOQ, Jetty, Spring, Hibernate, JUnit/Spock

Professional experience

Lead Software Engineer at Revolut 03/2023 - 05/2025

Stack: java17, gcp, postgresql, jooq, ansible, teamcity

• Developed and launched Bizum (Spanish instant payments system)
• Developed and launched Cash Deposit product for European countries
• Oversaw development and launch of BLIK (Polish payments system)
• Led migration of iDEAL payments (Netherlands) to a new API
• Led and mentored a team of 6 developers
• Conducted technical hiring interviews

Senior Software Engineer at Revolut 09/2020 - 02/2023

Stack: java11, guice, gcp, postgresql, jooq, ansible, teamcity

Revolut is a unicorn neo-bank. I worked in Core Payments department, developing and maintaining Bank Transfers product.

• Developed and launched an integration with a major bank in APAC region
• Developed Confirmation Of Payee service for UK market
• Developed FPS and BACS services for UK market
• Optimized performance of a business-critical integration (processes 20% payments)
• Led and mentored a team of 3 developers
• Conducted technical hiring interviews

Expert Software Engineer at Auto1 07/2019 - 08/2020

Stack: java8, spring5, aws, consul, postgresql, redis

Europe’s leading online B2B marketplace for used cars. I was working in the Core Team which focused on the internal software ecosystem. We did company-wide refactorings, supported common libraries and provided other teams with tools to increase their productivity.

• Promoted after 6 months because of outstanding performance
• Facilitated migration of ~300 java APIs to OpenAPI by creating tooling
• Reduced AWS costs by investigating spring-boot apps startup time and memory consumption and finding a way to lower it
• Streamlined migration to spring5/spring-boot 2.x through comprehensive overhaul of dependency tree and refactoring common libraries

Senior Kotlin Developer at HortiCloud 05/2018 - 06/2019

Stack: kotlin, ebean, hk2, aws kinesis/ebs/redshift/rds/s3, jetty, terraform, reactjs, clickhouse, postgresql, letsencrypt

HortiCloud: An agri-tech startup developing data collection and analytical dashboard solutions for modern greenhouses.

• Implemented a system for unattended upgrades of our software installed on customer climate computers
• Created admin interface (reactjs) to automate routine customer supporting tasks
• Reduced AWS costs for development environments by 50% by eliminating ALB
• Improved graph plotting performance by replacing Redshift with ClickHouse
• Brought in Terraform to describe and maintain AWS infrastructure

Development Lead at [SRG] 02/2015 - 05/2018

Stack: java8, spring4, spring-boot, thymeleaf, nginx, puppet, jetty, tomcat7, grafana, zabbix, jenkins, mysql, redis

A real estate analytics firm providing ML-driven property valuations for banks. Joined as Senior, progressing to lead all technology functions.

• Optimized and enhanced core ML algorithms for property valuation
• Migrated company to infrastructure-as-a-code (puppet)
• Implemented monitoring and alerting (zabbix)
• Significantly reduced time for a daily data scrape by redesigning the scraping robot from scratch
• Made process of gathering data predictable and measurable by introducing metrics collection and analysis (grafana, statsd)
• Got awarded with “Employee of the Year”
• Conducted over 40 technical interviews

Senior Software Engineer at TezTour 09/2011 - 02/2015

Stack: java7, maven, jenkins, oracle+pl/sql, spring, hibernate, jquery, gwt, jsp

One of the biggest tour operators in Russia. I was the main developer of a CRM system for travel agencies. Also with the help of business analytic I designed and implemented a B2C solution for direct tour sales from the company website.

• Reduced codebase by a factor of three by upgrading gwt from 1.6 to 2.4
• Reduced boilerplate code by introducing spring annotations and lombok
• Introduced CI in the company (jenkins)
• Introduced automated Selenium testing
• Optimized PDF generation and reduced file size from 1mb to 100kb

Junior Java Developer at John Wiley and Sons 11/2010 - 08/2011

Stack: ejb, jsf, marklogic

Wiley is a well-known book publisher and they had IT department in my city. After several months sabbatical I’ve decided to pivot my career from Perl to Java and got into the company. As a junior java developer I’ve closed a lot of long-standing bug reports.

Sabbatical 03/2010 - 10/2010

I did some freelancing, but mostly I was just enjoying my life.

Software Developer at Yandex 01/2008 - 02/2010

Stack: perl, mapreduce, amcharts

Hugely popular “russian Google”. I was working in the statistics department. Our team was developing an internal analytics platform akin to Google Analytics, which used access logs as a source. I had to work with terabyte sized databases and to write effective aggregating SQL queries. My main duty was to implement statistical reports that were requested by other teams and used for A/B testing or KPI measurements.

• Improved UX for working with data by replacing statically generated graphs by interactive charting engine

Software Developer at Rambler&Co 06/2006 - 12/2007

Stack: Perl, SQL, HTML, CSS, Postgresql

Rambler is one of the oldest russian IT companies. Started as a search engine now it’s a big media holding that operates multiple websites. I was working on Rambler’s early social network “Planeta”. Despite it wasn’t very popular - the website received enough traffic so that performance started to matter. Here I learned about caches and their invalidation, database replication, scheduled backups, SQL query optimization. And obviously lots of HTML/CSS.

• Designed and implemented SMS voting system

Education

2004-2009 Moscow State Technical University Engineer of Metalworking Machines

2016-2019 Moscow State Institute of Radio Engineering, Electronics and Automation BSc in Computer Software Engineering

Constantly educate myself with various online courses and side projects.