Nikolai Golub, Software Developer in Amsterdam, Netherlands
Nikolai Golub

Software Developer in Amsterdam, Netherlands

Member since December 28, 2014
Nikolai is a self-directed and organized professional. He is a results-oriented problem solver with sharp analytical abilities and excellent communication skills. He is a highly competent software engineer with four years of experience in Python programming and web technologies.
Nikolai is now available for hire

Portfolio

  • ConsenSys
    Rust, Go, Java, Solidity, Apache Kafka, Amazon Web Services (AWS), Back-end...
  • Booking.com
    Continuous Integration (CI), Apache Kafka, Kubernetes, MySQL, Java...
  • EverCharge (via Toptal)
    Full-stack, Unit Testing, SQL, JavaScript, Back-end...

Experience

Location

Amsterdam, Netherlands

Availability

Part-time

Preferred Environment

Vim Text Editor, MacOS, Linux, IntelliJ, Docker

The most amazing...

...application I've built uses Django to store performance test results, involving millions of metrics and integration with systems and APIs like Jira and Zabbix.

Employment

  • Protocol Engineer

    2021 - PRESENT
    ConsenSys
    • Implemented contract-based testing between different components, which reduced integration-type bugs.
    • Optimized smart contract in Solidity to reduce transaction cost.
    • Enhanced integration of Rust library into Java codebase using the Java Native Interface.
    • Benchmarked and optimized high-performance computing (HPC).
    Technologies: Rust, Go, Java, Solidity, Apache Kafka, Amazon Web Services (AWS), Back-end, PostgreSQL, Docker, Blockchain, Concurrent Programming, Asynchronous Programming, Cryptography, Continuous Integration (CI), Unit Testing, Performance Optimization, GitHub, Ethereum, Algorithms, Grafana
  • Software Developer

    2017 - 2021
    Booking.com
    • Implemented a set of A/B experiments, which reduced cancellations-related customer support tickets by 20%.
    • Improved performance of entrepreneurial partners by integrating a cancellation policy recommendation model.
    • Completed full API integration with tours and activities providers, which increased transactions by 10%.
    • Contributed to community-driven projects, including Python libraries and developer tools.
    Technologies: Continuous Integration (CI), Apache Kafka, Kubernetes, MySQL, Java, Database Design, Cassandra, Object-oriented Programming (OOP), RESTful APIs, Microservices, Grafana, A/B Testing
  • Software Developer

    2015 - 2019
    EverCharge (via Toptal)
    • Introduced database schema migration using Alembic and Flask-Migrate.
    • Developed a web portal from scratch using Flask-Admin.
    • Introduced automated tests, including unit, integration, and Selenium-based tests. Improved coverage of the Python codebase to 90%.
    • Developed a customer signup flow, which includes handling Stripe payments.
    • Decreased the cost of monthly billing procedures by moving it from FreshBooks to Stripe.
    • Automated the reimbursement procedure, including issuing a lob.com check.
    • Configured deployments on AWS Elastic Beanstalk using Docker.
    • Created a set of tools for validating data from devices.
    Technologies: Full-stack, Unit Testing, SQL, JavaScript, Back-end, Amazon Web Services (AWS), Docker, Git, Stripe API, GitHub, PostgreSQL, Python, Celery, Redis, Stripe, SQLAlchemy, Flask, Database Design, Algorithms
  • Front-end Developer

    2016 - 2017
    Staffmatch (via Toptal)
    • Implemented vector animation for the main website.
    • Added automated tests for core web logic for faster refactoring.
    • Refactored UI logic, which reduced the number of bugs.
    Technologies: Unit Testing, Webpack, Redux, React, CSS, CSS3 Animation
  • Python Web Developer

    2015 - 2015
    Walkio (via Toptal)
    • Added features that allow customers to communicate via Twilio SMS.
    • Migrated the data model to remove logical inconsistencies.
    • Added integration with Checkr.io for background checks on prospective dog walkers.
    • Set up a two-step sign-up for dog walkers.
    • Added an editing page for account details and billing information.
    • Increased unit test coverage from 0 to 87 percent and included Selenium tests.
    Technologies: Full-stack, Unit Testing, SQL, JavaScript, Back-end, Git, Stripe API, Python, Twilio, Stripe, PostgreSQL, Django, Database Design
  • Python Test Automation Developer

    2014 - 2015
    Positive Technologies
    • Created a Python module for generating data for load testing using Yandex.Tank.
    • Created software for advanced test artifact collecting. Facilitated analysis of new bugs.
    • Implemented an abstraction layer for simpler web UI testing. Reduced the support cost of tests.
    • Moved auxiliary services to the Docker. Decreased resource usage of the test environment.
    Technologies: Nginx, Unit Testing, SQL, Networks, Grafana, Git, GitLab, Elasticsearch, MongoDB, Docker, Python
  • Performance Engineer

    2012 - 2014
    Dino Systems
    • Suggested, designed, and developed a web portal for aggregation performance tests results. Reduced time spent on report creation by 30%. Used Django, PostgreSQL, Celery, and amCharts.
    • Created a cross-platform desktop application for tracking time for Jira issues. Improved time tracking accuracy significantly.
    • Developed performance tests for a SOAP API service using C#.
    • Designed and developed advanced performance tests for a telephony system.
    • Developed a script for creating test cases in a test case management system from real HTTP traffic.
    Technologies: Unit Testing, SQL, Networks, Git, PostgreSQL, Celery, Django, Subversion (SVN), R, AmCharts, jQuery, Python, C#, Zabbix, Performance Analysis
  • Performance Engineer

    2011 - 2012
    Devexperts
    • Developed a script for automatic collection and result processing of performance tests. Decreased the number of human errors and data losses.
    • Designed and successfully ran performance tests for an industrial monitoring system on a tight schedule.
    • Set up an environment for monitoring and collecting results in Amazon EC2.
    • Introduced an advanced configuration of a monitoring system. Reduced the load to the monitoring system MySQL database and improved performance.
    • Performed a migration to a new OS testing images in Amazon EC2.
    Technologies: Unit Testing, SQL, Amazon Web Services (AWS), Networks, AWS EC2, MySQL, Subversion (SVN), Linux, Java, Performance Analysis

Experience

  • PyJTT
    https://github.com/citizen-stig/pyjtt

    A desktop application for tracking time in Atlassian Jira. It works with Jira's REST API and is supported on Mac, Windows, and Linux. It uses SQLite as local storage. This app was successfully used in the performance team at Dino Systems.

  • KidStat

    A web application that provides categorization of child growth standards, using world health organization data. It is built on top of Flask, MongoDB and React. Source code is available on GitHub: https://github.com/citizen-stig/kidstat.

  • Performance Dashboard

    A Django-based dashboard for storing and analyzing performance test results.
    It stores metrics from servers under tests and from test clients, builds graphs, and performs data aggregation.
    My contributions to the project allowed the decrease of time spent on creating performance reports by approximately 30%.

  • Single Page about the Marathon in Saint Petersburg

    It uses MongoDB for storing data and amCharts for representing it.

    It uses Babel for multi-language support.

    Sources: https://github.com/citizen-stig/ergo_white_nights

  • Log Trimmer
    https://github.com/citizen-stig/logtrimmer

    A script that allows users to cut off part of the log file using 2 timestamps. It uses binary search, so it's efficient even on large log files.

  • Python Best Practices and Tips by Toptal Developers (Publication)
    This resource contains a collection of Python best practices and Python tips provided by our Toptal network members.

Skills

  • Languages

    Python, Rust, JavaScript, Java, SQL, HTML, Go, Solidity, CSS, Perl
  • Frameworks

    Flask, Bootstrap, Redux, Django, JUnit
  • Paradigms

    Automated Testing, Database Design, Object-oriented Programming (OOP), Unit Testing, Continuous Integration (CI), Test-driven Development (TDD), Asynchronous Programming, Concurrent Programming, Microservices
  • Platforms

    Amazon Web Services (AWS), Linux, Docker, Kubernetes, Twilio, Heroku, Apache Kafka, Blockchain, Ethereum
  • Storage

    PostgreSQL, NoSQL, Redis, MongoDB, MySQL, Elasticsearch, Cassandra
  • Other

    Performance Analysis, RESTful APIs, Performance Optimization, Front-end, Back-end, APIs, Algorithms, Full-stack, Cryptography, Networks, Network Programming, A/B Testing, CSS3 Animation
  • Libraries/APIs

    React, SQLAlchemy, Stripe, Stripe API, PyQt
  • Tools

    Celery, GitHub, Nginx, Git, GitLab, Babel, Webpack, Maven, Grafana
  • Industry Expertise

    Security

Education

  • Master's Degree in Management and Technology for Information Security
    2006 - 2012
    Saint-Petersburg State University (Information Technologies, Mechanics, and Optics) - Saint Petersburg, Russia

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