Yaroslav is available for hire
Hire YaroslavYaroslav Lepenkin
Verified Expert in Engineering
Kotlin Developer
Dubai, United Arab Emirates
Toptal member since March 23, 2021
Bio
Yaroslav started his career at JetBrains in 2012, working on IntelliJ IDEA, a popular Java IDE. Later, he became a technical co-founder of MACAW, where he was in charge of building and launching the product from scratch. Yaroslav's main expertise areas are the JVM ecosystem: Java and Kotlin programming languages, Python and Django framework, MongoDB and PostgreSQL databases, and Elasticsearch.
Portfolio
Kizen Technologies, Inc.
Kubernetes, PostgreSQL, Python, Django REST Framework, ClickHouse...
Macaw
Planning, Management, Education
MACAW
Kotlin, Dropwizard, MongoDB, PostgreSQL, Elasticsearch, Redis, Puppeteer...
Experience
- Java - 9 years
- Java Concurrency - 9 years
- Databases - 7 years
- Kotlin - 6 years
- PostgreSQL - 4 years
- Data Scraping - 4 years
- Django - 3 years
- Elasticsearch - 1 year
Availability
Full-time
Preferred Environment
IntelliJ IDEA, MacOS
The most amazing...
...thing I've invented is a feature in IntelliJ, never seen before in the IDEs, which users loved and even requested from the competitor IDE.
Work Experience
Elasticsearch Expert
2021 - 2023
Kizen Technologies, Inc.
- Developed an automation engine, allowing the customers to perform sets of actions in an automated fashion. It supports sending messages, evaluating conditions, modifying fields, and waiting for particular user actions.
- Developed a record timeline infrastructure. That includes also creating an infrastructure for creating and maintaining PostgreSQL partitioned tables by leveraging Django commands, cron jobs, and Kubernetes.
- Greatly improved developer productivity. Made it possible to run tests in parallel; restructured Docker build to minimize building time by using the base image; and sped up database migrations by using a database dump.
- Improved the testing infrastructure by creating three separate sets of tests (integration testing with Kafka, unit testing with Kafka, and regular unit tests) and created a configurable Jenkins job for that.
- Prepared lectures for the team about writing clean code, database transactions, Django signals, and the things I was working on.
Technologies: Kubernetes, PostgreSQL, Python, Django REST Framework, ClickHouse, Elasticsearch, Jenkins, Python 3, Django, Databases, HTML, CSS, Architecture
Director of Engineering
2019 - 2021
Macaw
- Led product development and planned new features and product infrastructure enhancements.
- Coached and reviewed the work of the back-end team. Shared my knowledge of database systems, web application reverse engineering, and mobile application reverse engineering.
- Managed deployments, data integrity, and backups, ensuring seamless system functionality.
Technologies: Planning, Management, Education
Founding Engineer
2017 - 2021
MACAW
- Developed social network parsers for the largest social networks in Russia, VK, and OK.ru, which required web scraping of the browser versions and reverse engineering of Android and iPhone mobile applications.
- Implemented the back-end API using Dropwizard framework, Kotlin, MongoDB, and Elasticsearch.
- Implemented the back end of an internal admin application using Kotlin and Dropwizard, which works as a CRM and provides meaningful metrics fetched from all the project data sources, specifically PostgreSQL, MongoDB, Redis, and Elasticsearch.
- Took care of the internal infrastructure and introduced Docker, Kubernetes, and Helm to our deployment pipelines.
- Implemented the Facebook Ad Library parser and scaled it to handle two million new banner ads daily.
Technologies: Kotlin, Dropwizard, MongoDB, PostgreSQL, Elasticsearch, Redis, Puppeteer, Node.js, Docker, Kubernetes, Helm, Web Scraping, Reverse Engineering, Java Concurrency, Back-end, APIs, Amazon S3 (AWS S3), JavaScript, Containerization, Amazon Web Services (AWS), Data Scraping, Databases, Data Extraction, HTML, CSS, Architecture, Front-end, Vue
Software Engineer
2012 - 2017
JetBrains
- Maintained and improved general code formatting engine, a framework for developing code formatters for any language supported by IntelliJ and its Java implementation. The main inspiration came from the user reports.
- Developed and launched a plugin for A/B testing of "machine-learned" code completion algorithms, which reported code completion data and reordered completion items.
- Invented and implemented the prototype of a new feature, parameter name hints, that showed parameter names for literals passed as arguments, tested it, and then implemented the production level feature with the help of UX and UI engineers.
Technologies: Java, Kotlin, Gradle, Java Concurrency, Algorithms
Experience
Secure Telegram Client For Business
https://app.besync.proA small Telegram client with the ability to associate a tag with a Telegram chat, filter by tag, and create message drafts or send messages to selected contacts. The project does not have back-end. All the user data is stored in the browser. I've built the whole project myself and simplified the life of a couple of my friends.
Macaw Tool
https://macawpro.medium.comA tool for monitoring ads in social networks, helping people make their own ads better. The project is closed, but you can take a look at the screenshots. I have built web parsers, the back end for a product, and both the front and back ends of the admin application for marketing teams.
IntelliJ Completion Stats Collector
https://github.com/JetBrains/intellij-stats-collectorA plugin initially made for collecting code completion data and A/B testing of machine learning code completion ordering algorithms. I made the initial version of a plugin that collected data and allowed the reordering of the completed items using the given algorithms.
A/B Testing of a Google Play Application Page
A Spring Boot application that allows users to test the CTR and install rate of not yet existing Android applications to prevent wasting money on building something people aren't interested in. It also allows them to perform A/B tests to find which texts and images convert better. The app is used internally in our company.
Shared Library
https://shared-library.appspot.comThis project helps to share books between people. You sign up via your social network account, add the books you want to share, and browse books other people have added to the shared pool. The project was written using Angular 1 and Python Google Cloud.
Education
2011 - 2013
Master's Degree in Software Engineering
Saint Petersburg Academic University - Saint Petersburg, Russia
2007 - 2011
Bachelor's Degree in Physics
Saint Petersburg State Polytechnic University - Saint Petersburg, Russia
Certifications
MAY 2019 - PRESENT
Cryptography 1
Stanford Online | via Coursera
JUNE 2017 - PRESENT
Operating Systems Introduction Course
Stepik
Skills
Libraries/APIs
Puppeteer, Node.js, Vue, Telegram Messenger API
Tools
Java Concurrency, Gradle, Helm, Jenkins, NPM
Languages
Java, Kotlin, Python, Python 3, SQL, JavaScript, CSS, HTML
Frameworks
Dropwizard, Django, Spring Boot, Micronaut, Spring, Django REST Framework, Angular
Storage
MongoDB, PostgreSQL, Elasticsearch, NoSQL, Databases, Redis, MySQL, Amazon S3 (AWS S3), ClickHouse, Google Cloud
Paradigms
Management
Platforms
Docker, Kubernetes, Amazon Web Services (AWS)
Other
Web Scraping, APIs, Data Scraping, Data Extraction, Architecture, Algorithms, Containerization, Reverse Engineering, Cryptography, Physics, Back-end, Front-end, Planning, Education, Virtual Machines
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