Andrey Sinitsyn
Verified Expert in Engineering
Back-end Developer
Udine, Province of Udine, Italy
Toptal member since September 2, 2014
Andrey is a developer with more than 15 years of experience in various projects, including advertising, social networks, CRM, and complex sectoral projects. Andrey has worked at all levels of responsibility, from being a developer to chief technical officer.
Portfolio
Experience
- Python - 19 years
- Back-end Development - 19 years
- PostgreSQL - 15 years
- Django - 11 years
- Amazon Web Services (AWS) - 10 years
- Architecture - 8 years
- Agile Software Development - 5 years
- Oracle 11i - 2 years
Preferred Environment
Vim Text Editor, PyCharm, MacOS, Ubuntu, Linux
The most amazing...
...task I've handled is the technical management of an eLearning project from scratch up to the launch of the "box version."
Work Experience
Back-end Python and Django Developer
Solvency II Wire
- Developed complex business logic features for the project in a limited time with a short onboarding process.
- Improved the project's back end performance by rewriting complex SQL queries and offloading long-running tasks to the asynchronous background running tasks.
- Provided important insights on existing project architecture thus allowing to successfully refactor legacy code and reduce code dependencies.
Senior Developer
Medical Devices Company
- Maintained and improved a proprietary PyQt application with complex business logic, delivering new features, refactoring legacy code for improved maintainability, integrating Azure cloud services, and building CI/CD pipelines for release workflows.
- Built a multi-project release pipeline for offline firmware and software updates on a medical device, targeting Toradex Verdin-family CoMs with custom Yocto embedded Linux builds.
- Created an end-to-end testing framework for a four-device embedded medical system, supporting functional and E2E test execution across multiple protocols and generating detailed reports for official regulatory evaluations.
- Established cross-platform test infrastructure by integrating Wine and custom C bindings to run a Windows application's automated test suites natively on Linux, eliminating platform dependency from the release pipeline.
Senior Developer
AI-powered Learning Content Platform (via Toptal)
- Built the back end for an AI-powered learning platform enabling educators to generate rich multimedia courses using LLM APIs (OpenAI, Anthropic).
- Designed and implemented FastAPI services powering multi-agent workflows that combined user data sources, external tools, and RAG pipelines to produce structured, personalized learning content.
- Created the core back end from scratch, including the content generation engine, context aggregation layer, and API platform.
- Delivered a scalable, production-grade system supporting dynamic content synthesis across text, video, and interactive formats.
- Integrated vector databases for semantic retrieval and developed scraping and indexing pipelines to feed the knowledge base.
Python Developer
Motorola Solutions
- Participated in the company's Digital Transformation program, which included providing solutions for complex business requirements, working with multiple databases and APIs, and DevOps.
- Improved overall quality of the project code by introducing TDD practices and DRY and KISS principles. This helped to reduce development and testing times and raise website stability significantly.
- Introduced a workflow that flexibly accommodated business requirements and timelines without penalizing feature development.
- Successfully migrated project code, including dealing with complex code and 3rd-party and DB dependencies, from Python 3.6 to Python 3.10.
- Actively participated in architecting and developing high-performance solutions to accommodate complex business requirements.
Senior Software Developer
Quokky SRL
- Solidified architectural decisions for overall product improvement.
- Changed the product notification system from polling to web sockets.
- Delivered a framework for data extraction from PDF documents.
- Built document classification improvements with RNN.
- Improved the company's testing and deployment processes with CircleCI and SaltStack.
CTO
BirdieFire LLC
- Reviewed, proposed, and implemented the new architecture to resolve the project's bottlenecks.
- Refactored and improved the legacy code used on the project, including outdated dependencies.
- Migrated project from Python 2 to 3, including upgrading the Django version from 1.4 to 1.11.
- Migrated DB from MySQL to PostgreSQL with a bit of downtime.
- Created audio/video processing pipelines for the game's videos with tagging.
Remote Developer
Hukkster
- Wrote 50+ parsers for different online stores by using Python scraping tools.
- Contributed to the project's global library code improvements.
- Refactored and improved the legacy codebase used on the project.
Developer
GERO
- Built a completely dynamic web form for a questionnaire, synchronized with the cloud.
- Improved implementations of an MTA algorithm for certain sets of data.
- Developed API providers to retrieve data from Nike+ and Jawbone user accounts.
- Created the first version of a company website using Django.
- Gained experience with mocking types of unit tests.
Chief Technical Officer
Action Learning
- Provided technical support for company business processes (Cloud virtual hosting for projects and development, Redmine, LDAP, Google Apps for domains, Sentry (remote logger), Jenkins (CI), and MediaWiki).
- Provided technical expertise and integration of products into different IT environments (SCORM-capable client LMSs, and remote UNIX systems).
- Created software architecture for the company's product.
- Developed an online course constructor capable of suiting various client needs.
- Hired and trained groups of developers for this project.
Experience
AI-powered Learning Content Platform (via Toptal)
GERO
Education
Master's Degree in System Analysis
Moscow Aviation Institute (State Technical University) - Moscow, Russia
Certifications
Machine Learning
Coursera
Algorithms: Design and Analysis, Part 1
Coursera
Skills
Libraries/APIs
Requests, REST APIs, Django ORM, React, API Development, Asyncio, SQLAlchemy, VK API, Tastypie, jQuery, OpenAPI, Matplotlib, Stripe API, AngularUI, X (formerly Twitter) API, NumPy, Instagram API, Restangular, Facebook API, Stripe, jQuery Mobile, Node.js, Pandas, Pydantic, PyQt
Tools
NGINX, Microsoft Excel, Microsoft Word, Celery, Git, IPython, RabbitMQ, Logging, Auth0, Amazon ElastiCache, SaltStack, uWSGI, Vim Text Editor, Haystack, Apache, Jira, Redmine, PyCharm, Amazon Simple Queue Service (SQS), GitHub, Pytest, Bitbucket, Claude Code, AWS IAM, Claude, Moodle, Subversion (SVN), Stash, Bamboo, Jenkins, Amazon Elastic Container Service (ECS), Slack, Docker Compose, GitLab CI/CD
Languages
JavaScript, Python, Perl, Python 3, CSS, HTML, SQL, XML/XSLT, Go, PHP, Ruby, Fortran, XML, GraphQL, Java, TypeScript
Frameworks
Django REST Framework, Django, LangGraph, Bootstrap, Bootstrap 3+, Flask, Next.js, Django Channels, PhoneGap, Ionic, AngularJS, Ruby on Rails (RoR), Symfony, GeoDjango, Angular, Scrapy, Alembic, NestJS
Paradigms
Agile Software Development, Waterfall Development, Testing, REST, Unit Testing, DRY, KISS, Agile, Back-end Architecture, Automation, Role-based Access Control (RBAC), Model Context Protocol (MCP), Functional Programming, Microservices, Microservices Architecture, Application Architecture, DevOps, Database Design, Test-driven Development (TDD), Management, Continuous Delivery (CD), Continuous Integration (CI), Serverless Architecture, ETL, Automated Testing, SCORM, Asynchronous Programming
Platforms
Amazon Web Services (AWS), Ubuntu, AWS Lambda, Linux, Debian Linux, MacOS, Docker, Azure, Amazon EC2, Google Cloud Platform (GCP), Apache Kafka, Red Hat Linux, Oracle, BigCommerce, Windows, Kubernetes, Viewflow, ARM Linux, Embedded Linux
Storage
PostgreSQL, Data Integration, JSON, Databases, Data Pipelines, InnoDB, MySQL, MyISAM, MongoDB, Redis, Memcached, Amazon Aurora, Amazon S3 (AWS S3), Elasticsearch, Oracle 11i, Sphinx Search Engine, Google Cloud
Other
Back-end Development, Web Development, API Integration, APIs, Back-end, Message Queues, Architecture, Cloud, Full-stack, Scripting, Software Architecture, Technical Leadership, eCommerce, RESTful Services, Git Flow, FastAPI, WebSockets, Web Scraping, Text Recognition, Optical Character Recognition (OCR), Proof of Concept (POC), Deployment, Code Review, Debugging, Data Engineering, OAuth, Integration, Legacy Code, Agentic AI, Large Language Models (LLMs), LangChain, RAG Systems, Data Management, Integration Testing, Communication, HTTP, Middleware, Team Management, Startups, API Design, Documentation, Software Engineering, System Architecture, Machine Learning, Scraping, CTO, System Architecture Design, Distributed Systems, Webhooks, Amazon RDS, CI/CD Pipelines, Graphical User Interface (GUI), eCommerce Development, Data Transformation, Performance Optimization, Leadership, Database Optimization, Engineering Management, Front-end Development, Full-stack Development, Serverless, API Gateways, Data Visualization, Data Scraping, Containers, Cloud Architecture, Solution Architecture, Artificial Intelligence (AI), SOLID Principles, Website Data Scraping, Queue Management, AWS Database Migration Service (DMS), AI Tools, ERP Systems, Workflow Automation & System Integration, ETL Pipelines, Minimum Viable Product (MVP), Fractional CTO, Enterprise Systems, Third-party APIs, Third-party Integration, Algorithms, Computer Science, GraphDB, Cordova, Aerospace & Defense, Satellite Images, Systems Analysis, Organization, Aeronautics, Aerodynamics, Queueing Theory, Containerization, Multitenancy, Scalability, Project Planning, Delivery Management, GitHub Actions, Cryptography, Lambda Functions, Mathematics, Statistics, Retrieval-augmented Generation (RAG), Vector Databases, Multistage LLM Chains, Anthropic, OpenAI, Scalable Vector Databases, Front-end, Web Crawlers, Clang, ARM SoC, Document Processing
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