Oleg Schalginski
Verified Expert in Engineering
Software Developer
Dortmund, North Rhine-Westphalia, Germany
Toptal member since February 16, 2022
Oleg is a software developer with over 20 years of experience automating business processes for various industries, including construction, finance, energy, telecom, and government. He has experience using various technologies, including JavaScript, TypeScript, PHP, MySQL, Oracle, Redis, and DynamoDB for storage, as well as frameworks, including .NET, Symfony, React, and Redux. Oleg's goal remains constant—to deliver uber-flexible, user-friendly interfaces that meet business needs.
Portfolio
Experience
- JavaScript - 20 years
- PHP - 20 years
- MySQL - 20 years
- React - 6 years
- Symfony - 5 years
- Node.js - 5 years
- Amazon Web Services (AWS) - 3 years
- TypeScript - 3 years
Work Experience
Full-stack Python/React Developer
Tempus Research Group LLC
- Architected real-time AI chat streaming system using SSE, implementing multi-phase response handling with reasoning indicators, message buffering, and graceful error recovery across 12 back-end services.
- Integrated multi-provider LLM support (OpenAI, OpenRouter) with unified stream processing, file attachments via S3 storage, vector store management, and automatic citation extraction for document references.
- Delivered React front end with SWR data fetching, prompt version management, chat search, and Langfuse observability integration for end-to-end AI conversation tracing.
Full-stack Rust/Node.js/Next.js/NestJS Lead Developer + Architecture
David Johnson Smith
- Architected and built a full-stack trading infrastructure from scratch, including back-end, front-end, and Dockerized services, enabling scalable data pipelines and real-time trading dashboards.
- Designed and implemented real-time data ingestion systems collecting OHLCV and snapshot (orderbook) data from 8 crypto exchanges, processing over 2B events daily and storing 60B+ time-series records monthly using Timescale (PostgreSQL) and Cassandra.
- Designed, deployed, and maintained a robust AWS environment (ECS, EC2, ASG, ECR, ALB, RDS, etc.), and automated CI/CD pipelines with GitLab and Bitbucket to ensure high availability, zero-downtime releases, and cost-optimized scaling.
- Designed and implemented UI and data system development for a production-grade trading platform, including a customizable, real-time dashboard and an internal backtesting API for strategy research and performance evaluation.
Lead PHP/Next.js/C++ Developer + Architecture
Digital Places, LLC
- Moved the entire project to the new UX, including back compatibility.
- Refactored and implemented new business processes, including front and back end.
- Created a new 3D model file processing system design and implementation.
- Integrated Shopify to a VR environment through an API to allow the placement of goods right in experience.
Games Processing Team Lead
Oxtech LTD
- Developed a microservice architecture for processing games, serving millions of players.
- Optimized the code and data structure to improve performance, which allows processing of several hundred million transactions per month.
- Created the original game provider service to work with dozens of external aggregators, allowing the unification of numerous interfaces, reduction of code maintenance costs, and significant improvement of the quality and stability of performance.
Full-stack Developer
The ZYX Integrated Technologies
- Developed analytics reports (front and back end) based on two database instances (MySQL and Microsoft SQL Server).
- Created a digitalized application form processing with DocuSign and external credit report services integration.
- Built extensions for payment processes and data processing.
Tech Lead
Alar
- Developed a corporate information system that could be integrated with BIM, document flows, workflows, and financial items.
- Built integrated solutions for specific third-party software aimed at the construction industry.
- Created report systems based on face/finger recognition solutions for site management.
Head of the Development Center
Armada
- Developed a jury system for a government electronic project.
- Constructed an alternate civil service system for the Ministry of Labor.
- Built a system for mobile repair teams specifically helping them with geographically distributed objects.
- Developed dozens of services and components for a range of systems, including finance, workflows, and document flows.
Senior Developer
Compulink (Quorum)
- Developed a finance system for the finance department of the biggest mobile operator in the country.
- Constructed a warehouse management system that could be integrated with the customer's current document flow.
- Built dozens of components for corporate portals for the leading companies in a range of industries, including, oil, logistics, food, and steel.
Project History
Alternate Civil Service for the Ministry of Labor
Education
Master's Degree in Computer Systems and Networks
Bauman Moscow Technical University - Moscow, Russia
Skills
Libraries/APIs
React, Node.js, AWS Amplify, jQuery, REST APIs, Three.js, Binance API, OKX API, Kraken, Stripe API, Stripe, SQLAlchemy, OpenAI API
Tools
RabbitMQ, GitLab CI/CD, Bitbucket, HashiCorp Vault, Amazon Elastic Container Registry (ECR), Amazon Elastic Container Service (ECS), GitHub, Amazon Cognito
Languages
PHP, JavaScript, TypeScript, SQL, Python 3, C++, SCSS, HTML, CSS, Python, Java, Rust
Frameworks
Redux, .NET, Symfony, Laravel, Next.js, Swoole, NestJS, Tailwind CSS, LlamaIndex
Paradigms
REST, Microservices, PHP Standards Recommendations (PSR), Event-driven Design (EDD)
Storage
MySQL, Database Architecture, PL/SQL, MSSQLCE, Amazon DynamoDB, Redis, PostgreSQL, Amazon S3 (AWS S3), SQL Performance, Microsoft SQL Server, NoSQL, Cassandra
Platforms
Oracle, SharePoint, Amazon Web Services (AWS), Kubernetes, Docker, AWS Lambda, Shopify, Unix, Linux, MacOS, Windows, Amazon EC2, PagerDuty, Decentralized Exchanges (DEXs), Bybit, Langfuse
Other
Technical Leadership, Software Architecture, Amazon API Gateway, APIs, API Integration, High-load, Performance, PHP Performance, Sharding, Indexing, Caching, Front-end, WebSockets, BrainTree, Payment APIs, Card Payments, Business Reporting, Solution Architecture, Software, Hardware, Networks, DocuSign, 3D, Concurrency, Big Data, Fintech, Data Scraping, Data Cleansing, Timescale, TradingView, Crypto, CI/CD Pipelines, CEX, HTX, BitMEX, Deribit, Kucoin, ECS, GitHub Actions, Full-stack, Tailwind UI, FastAPI, OpenRouter, ChatUI, Large Language Models (LLMs)
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