Andrey Koltsov, Software Developer in Kraków, Poland
Andrey Koltsov

Software Developer in Kraków, Poland

Member since July 30, 2019
Andrey is a senior full-stack web developer with over 12 years of experience. Specializing in building back-end APIs for web applications, Andrey thoroughly understands the requirements for solid builds and always strives to provide the best infrastructures to safely and quickly facilitate growth and scaling.
Andrey is now available for hire




Kraków, Poland



Preferred Environment

Angular, Flask, Django, TypeScript, JavaScript, Python 3

The most amazing...

...full-stack project was for Trimble Connected Community where I developed with five different programming languages and worked with over 20 engineers.


  • Lead Python Developer

    2015 - PRESENT
    Epam Systems
    • Led a team in the creation of a web-based CRM for the HR department with automated email notifications, status tracking, and specialized tools like template insurance offering.
    • Integrated an application with APIs using JSON endpoints to reduce manual input.
    • Developed several Google Chrome extensions to improve the performance of people who work with internal systems.
    • Created samples for Google App Maker.
    • Improved application performance by optimizing SQL queries.
    Technologies: CSS, Chrome Extensions, Google Cloud Platform (GCP), Google App Engine, Google, Google Apps Script, TypeScript, JavaScript, Python
  • Senior Python Developer

    2010 - 2015
    • Worked to complete the development of a web application with many complicated forms.
    • Improved the performance of the back end.
    • Migrated the front end to Bootstrap so that the UI was consistent.
    • Added continuous integration based on Jenkins to run integration tests during the night on several agents to reduce testing time.
    • Created an office map system so my colleagues were able to find location information (floor, open space, and exact whereabouts) by first name, surname, or email.
    • Managed a team of one developer and three QAs.
    • Developed a REST API with a Django REST Framework.
    Technologies: Jenkins, jQuery, Bootstrap, JavaScript, Django, Python
  • Software Engineer

    2009 - 2010
    Omsk City Local Government Office: The Information and Communication Technologies Department
    • Worked to complete the development of a new city web portal:
    • Developed modules for Liferay CMS.
    • Created a REST API for integration with other departments, so they can automatically update their data on a web portal.
    • Introduced the use of a bug-tracker system.
    Technologies: jQuery, JavaScript, Liferay, Java
  • Developer

    2006 - 2009
    ISS Art, Ltd.
    • Created a back-end REST API using the Java Restlet framework and interfacing with a MySQL database.
    • Built a prototype of a single-page application (SPA) using the Ext JS framework.
    • Grew the front-end team that was building the SPA client.
    • Integrated Atlassian Bamboo for continuous integration.
    • Built an MVP of a cross-platform accounting application using C++ and the Qt framework.
    • Developed an application that merges a building plan of the object with Google maps with Flex and ActionScript.
    Technologies: PHP, ActionScript, JavaScript, Java, C++


  • Back End with Paywall

    I implemented the back end with Python/Django REST framework with Paywall.
    Paywall was implemented via Stripe subscription.
    Part of incoming and outgoing fields was stored in to avoid storing personal identification information (PII).
    The project was hosted on Heroku.

  • Web Interface for a SOAP Interface

    I developed a web interface and an ETL system.

    Project Details
    • Django Generated Web Page → Celery Task → Node.js App → SOAP Interface
    • Node.js App → REST Interface (Django REST Framework)
    • The eneration reports were in the MS Excel format

  • Back End and Web Client for Video Streaming

    Role: Full-stack Engineer

    Project Details:
    • Developed a back end and web client with the Django REST Framework and Celery for long-term tasks on the back end and Vuetify and Vue.js on the front end.
    • Deployed the application on AWS (EC2, S3, and Elastic Beanstalk) and the Amazon Rekognition Video API.
    • The video was streamed via Nginx, RTMP, and AWS CloudFront.

  • Web App for HR and Recruiters

    This project was for an NDA client.

    Here, I had to implement a web application for the HR/recruitment team. The app was built on top of an autoscaling platform to adapt to the current load and has several different access roles. The tool consists of several complex forms with interconnected widgets. I paid particular attention to accessibility.

  • Web App for Searching for Air Craft Spare Parts

    On this project, I worked under the NDA contract and I had to implement a web application that searched for airplane spare parts. The application consists of more than 30 forms that retrieve data from hundreds of tables.

    Technologies: Python, Django, JavaScript, jQuery, Bootstrap

  • Parse Real Estate Site for Flat Pics/Cost/Location

    Created a small parser for real estate site to extract data about flat cost, location(lat/long), pics, to show it a better way, lat long was used to make requests to google maps API to get information about near bus stops/ time to commute.

  • Trimble Connected Community

    I built a portal for large development companies.

    • Formalized customer wishes.
    • Developed the back end and CI.
    • Helped the front-end team.
    • Communicated with the C++ desktop client team.


  • City Government Portal

    Role: Full-stack Engineer

    • Converted client wishes into requirements.
    • Responsible for coding, deployment, and communication with the technical parts of other departments.

    Technologies: Java, JavaScript

  • Near Real-time ETL System

    I built a near real-time system.
    Income requests are handled by the Python/FastAPI server.
    Kafka (AWS Managed Kafka) was used as message bus.
    Workers were implemented with Python/Faust library.
    S3 was used as file storage.


  • Languages

    Python, Python 3, Google Apps Script, CSS, HTML5, JavaScript, TypeScript, SQL, ActionScript, C++, Java, PHP
  • Frameworks

    Django, Bootstrap 3, Scrapy, Swagger, JSON Web Tokens (JWT), Flask, Angular, Django REST Framework, Ext JS, Angular Material, Bootstrap 2, Bootstrap
  • Libraries/APIs

    REST APIs, jQuery, jQuery UI, Node.js, Django ORM, Google APIs, Vue.js, Asyncio, jQuery DataTables, Twitter API, Stripe, Stripe API, React
  • Tools

    VS Code, Celery, GitLab, IntelliJ IDEA, Jenkins, Git, Subversion (SVN), Sentry, Docker Compose, Auth0, Bitbucket, Alfresco
  • Paradigms

    REST, ETL, RESTful Development, Agile Software Development, Continuous Integration (CI), Continuous Development (CD)
  • Other

    Chrome Extensions, SOAP, APIs, RESTful APIs, FastAPI, Faust, Google, Liferay, Okta, Swagger/OAS, AWS MSK, Atlassian Jira, AWS
  • Platforms

    Heroku, Apache Kafka, Linux, Windows, AWS EC2, AWS Elastic Beanstalk, Google App Engine, Docker, Google Cloud Platform (GCP), AWS Lambda, Amazon Web Services (AWS)
  • Storage

    Google Cloud, Relational Databases, MySQL, PostgreSQL, Redis, AWS S3
  • Industry Expertise



  • Master's degree in Math and Computer Science
    2007 - 2009
    Omsk State University - Omsk, Russia
  • Specialist's degree in Math and Computer Science
    2002 - 2007
    Omsk State University - Omsk, Russia

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