Andrey Koltsov
Verified Expert in Engineering
Software Developer
Kraków, Poland
Toptal member since October 8, 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.
Portfolio
Experience
- JavaScript - 12 years
- SQL - 12 years
- Django - 9 years
- Python 3 - 9 years
- Django REST Framework - 3 years
- TypeScript - 3 years
- Flask - 3 years
- Angular - 3 years
Work Experience
Lead Python Developer
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.
Senior Python Developer
Luxoft
- 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.
Software Engineer
Omsk City Local Government Office: The Information and Communication Technologies Department
- Worked to complete the development of a new city web portal: Admomsk.ru.
- 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.
Developer
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.
Experience
Back End with Paywall
Paywall was implemented via Stripe subscription.
Part of incoming and outgoing fields was stored in verygoodsecurity.com to avoid storing personal identification information (PII).
The project was hosted on Heroku.
Web Interface for a SOAP Interface
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
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
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
Technologies: Python, Django, JavaScript, jQuery, Bootstrap
Parse Real Estate Site for Flat Pics/Cost/Location
Trimble Connected Community
https://www.myconnectedsite.com/Tasks:
• Formalized customer wishes.
• Developed the back end and CI.
• Helped the front-end team.
• Communicated with the C++ desktop client team.
Link:
• https://www.youtube.com/watch?v=GanAlW6SR_g
City Government Portal
http://admomsk.ru/Tasks:
• 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
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.
Education
Master's Degree in Math and Computer Science
Omsk State University - Omsk, Russia
Specialist's Degree in Math and Computer Science
Omsk State University - Omsk, Russia
Skills
Libraries/APIs
REST APIs, jQuery, jQuery UI, Node.js, Django ORM, Google APIs, Vue, Asyncio, jQuery DataTables, X (formerly Twitter) API, Stripe, Stripe API, React
Tools
Celery, GitLab, IntelliJ IDEA, Jenkins, Git, Subversion (SVN), Sentry, Docker Compose, Auth0, Jira, Bitbucket, Alfresco
Languages
Python, Python 3, Google Apps Script, CSS, HTML5, JavaScript, TypeScript, SQL, Flash 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
Paradigms
REST, ETL, RESTful Development, Agile Software Development, Continuous Integration (CI), Continuous Development (CD)
Platforms
Visual Studio Code (VS Code), Heroku, Apache Kafka, Linux, Windows, Amazon EC2, AWS Elastic Beanstalk, Google App Engine, Docker, Google Cloud Platform (GCP), AWS Lambda, Amazon Web Services (AWS), Memberstack
Storage
Google Cloud, Relational Databases, MySQL, PostgreSQL, Redis, Amazon S3 (AWS S3)
Other
Chrome Extensions, SOAP, APIs, FastAPI, Faust, Google, Liferay, Okta, Amazon MSK, Security
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