
Sergey Kolodiy
Verified Expert in Engineering
.NET Developer
Moscow, Russia
Toptal member since October 27, 2014
Sergey is a software engineer with extensive development experience in the .NET technology stack, with strong architecture and coding skills. He loves to work on complex and business-critical tasks with full involvement, high productivity, and great enjoyment. He is a big fan of clean, testable, and maintainable code and has worked on a number of successful projects ranging from small startups to complex enterprise applications.
Portfolio
Experience
- C# - 15 years
- REST - 10 years
- Unit Testing - 10 years
- ASP.NET Web API - 9 years
- .NET Core - 8 years
- TypeScript - 3 years
- Microservices Architecture - 2 years
- Algorithmic Trading - 2 years
Availability
Preferred Environment
Git, Visual Studio, Windows, .NET, Microsoft Visual Studio, C#, C#.NET, Visual Studio Code (VS Code), Full-stack Development, GitHub
The most amazing...
...application I've created is a tool that generates an OData REST API and a single-page web UI for any relational SQL database.
Work Experience
Founder
Orthogonal
- Designed and developed a generative MIDI sequencer for Ableton Live, using Max for Live and Typescript, that allows users to create complex and varied musical patterns with minimal input.
- Launched and maintained a professional website for the product, using Docusaurus and React, that showcases its features, benefits, and pricing and provides a landing page for potential customers.
- Created and updated user documentation, including an installation guide, user manual, and getting started guides, using Docusaurus and React, that help users get started and use the product effectively.
- Managed and coordinated the work of external freelancers, who produced video overviews and voiceover instructions for video tutorials that demonstrate the product's functionality.
- Conducted and implemented manual and unit testing, user feedback, UI and UX research, and other quality assurance methods that improved the product's performance, usability, reliability, and customer satisfaction.
Software Engineer | Analyst
Independent Project
- Designed and developed a successful algorithmic trading solution.
- Implemented various data analytics algorithms and several trading strategies.
- Integrated the solution with Telegram bot API for remote management.
Senior Software Engineer
BoostLingo, LLC
- Worked on new business-critical features in a fast-paced environment, fixed bugs, and refactored legacy code.
- Worked on all aspects of the system, including business logic workflows implementation, task analysis, third-party systems and services integration, back-end APIs and web client development, and much more.
- Made a performance audit and improved the performance of critical back-end APIs.
- Implemented a bunch of useful ASP.NET Core extensions and middleware, such as online user tracking and CSP handling.
- Achieved such exceptional project results with a Toptal client that I was bought out and started working with the client directly as a remote contractor.
Senior Software Engineer
Shrader Group LLC
- Designed and implemented an ETL pipeline to migrate a large amount of data from a legacy Drupal-based system to the new SQL Azure database.
- Performed a codebase audit and fixed some serious issues related to security, database versioning, testability, and overall code quality.
- Made a performance audit and improved the performance of critical APIs up to ten times.
- Implemented continuous integration pipelines in VSTS.
Senior Software Engineer
FRONTSTEPS
- Implemented a centralized security token service and a granular permission-based authorization system for ASP.NET Core instead of coarse-grained role-based authorization.
- Implemented an automated voicemail system with voice recognition so homeowners can register their visitors by phone, and community guards will be immediately notified about new guest invitations.
- Built a notification API to deliver various notifications to the platform users.
- Implemented a bunch of useful ASP.NET Core extensions and middleware, such as a distributed cache with fallback logic.
- Worked on CI-related stuff, including continuous delivery pipelines and package management.
- Worked on payment systems integration, back-end APIs, web and desktop clients, and more.
Senior Software Engineer
Infor
- Implemented an administration API with AWS integration for automatic code deployment.
- Created an administration REST service and AngularJS-powered single-page web application on top of it.
- Worked on new features, fixed bugs, and refactored legacy code.
Software Engineer
Freelance
- Implemented a web application for real-time server performance monitoring.
- Created a chart control with the D3.js library and helped the client avoid using commercial charting libraries.
- Implemented a REST API for one of the projects from scratch.
- Implemented an efficient parallel data parser for MediaWiki API.
Senior Software Engineer
T-Systems International
- Implemented new functionalities and business logic for desktop and web applications.
- Helped integrate the software system with external services like SAP and others.
- Provided on-site application support and helped resolve issues on the customer's site.
- Helped to meet a bunch of important deadlines during the project's lifetime.
- Made a presentation on code review and best practices applicable to it.
Software Engineer
ETNA Software
- Designed and developed a bunch of core system components: back-end APIs, services, and libraries for the sogotrade.com trading platform.
- Implemented and supported streaming and load balancing solutions for real-time market data delivery.
- Integrated back-end components with the customer's service monitoring system.
- Developed a market data provider with a web-based admin panel and AmiBroker integration.
- Introduced unit testing practices and testable code concepts to the project.
Experience
Flow: Generative MIDI Sequencer
https://orthogonal.one/products/flowFlow uses state machines under the hood and allows users to compose music algorithmically by defining simple steps and rules that determine how the music will change over time. The user defines the rules, and Flow executes them, producing infinitely long and varying musical patterns.
Boostlingo Platform
https://boostlingo.comSogotrade.com Trading Platform
http://sogotrade.com/ETNA Trader
https://www.etnasoft.com/etna-trader/ASPro
The system consists of two major parts: a desktop workstation for the technical inspection of cars and other vehicles and a web application for organizing drivers' license exams, surrounded by a set of back-end services and external systems.
Infor Learning Management System
PolyGen
https://github.com/sergey-kolodiy/PolyGenMicrosoft Certified Professional
https://mcp.microsoft.com/Anonymous/Transcript/ValidateTo validate the certification, use the following information:
Transcript ID: 1166968
Access Code: F4163941
Functional Programming Principles in Scala
https://www.coursera.org/verify/TN47UQ4G6AStack Overflow — Top 7% Overall
http://stackoverflow.com/users/3478087Seventy-seven answers were given.
Active in C#, .NET, ASP.NET, ASP.NET Web API, Unit testing, and Entity Framework. Top 7% overall.
Education
Bachelor's Degree in Information Systems and Technologies
Voronezh Institute of High Technologies - Voronezh, Russia
Certifications
Microsoft Certified Professional
Microsoft
Microsoft Specialist: Programming in C#
Microsoft
Functional Programming Principles in Scala
Coursera
Skills
Libraries/APIs
LINQ, Web API, React, API Development, Entity Framework, REST APIs, Moq, Node.js, SignalR, PubNub, SendGrid API, Twilio API, D3.js, Telegram Bot API
Tools
Visual Studio, Microsoft Visual Studio, GitHub, Azure DevOps Services, Git, Fiddler, Roslyn, Chrome Developer Tools, MSTest, Kafka Streams, SendGrid, Postman, Trello, Jira, Twilio Programmable Video, Zoom, Figma, AutoHotkey
Languages
Markdown, C#, JavaScript, C#.NET, T-SQL (Transact-SQL), HTML, SQL, TypeScript, Java, Scala, CSS
Frameworks
ASP.NET, .NET Core, ASP.NET Core, .NET, ASP.NET Web API, ASP.NET MVC, Angular, Entity Framework Core, Entity, NUnit, AngularJS, IdentityServer 4, Bootstrap, ASP.NET Identity, OAuth 2, Jest, Docusaurus
Paradigms
REST, Unit Testing, Object-oriented Programming (OOP), Dependency Injection, Object-oriented Design (OOD), Inversion of Control, Event-driven Architecture, Refactoring, Scrum, Microservices Architecture, Microservices, Functional Programming, Metaprogramming, Design Patterns, Azure DevOps, Agile, DevOps, Back-end Architecture, Object-relational Mapping (ORM), Event-driven Programming, ETL, Test-driven Development (TDD), Agile Software Development, UX Design, UI Design
Platforms
Visual Studio Code (VS Code), Azure, Twilio, Windows, Amazon Web Services (AWS), Arduino, Web
Storage
Microsoft SQL Server, SQL Server Management Studio (SSMS), Redis, NoSQL, IIS SQL Server, Database Architecture, Data Integration, SQL Server Integration Services (SSIS), MySQL, JSON
Other
SOLID Principles, .NET 6, APIs, Task Analysis, Back-end, Debugging, Web Development, Full-stack Development, Full-stack, Solution Architecture, .NET 7, Code Auditing, Single-page Applications (SPAs), Identity Server, Algorithmic Trading, Microsoft Azure, Source Code Review, Code Review, CI/CD Pipelines, Architecture, Mathematics, Software Architecture, Max for Live, API Integration, Windows Services, Performance, Cloud Architecture, System Integration, SaaS, Web Applications, Distributed Systems, Data Structures, Cloud, Subscriptions, Data Mining, OWASP, OAuth, Performance Analysis, Microsoft Data Transformation Services (now SSIS), Domain-driven Design (DDD), Windows Communication Foundation (WCF), Trading, Stock Price Analysis, User Interface (UI), User Experience (UX), Front-end, MIDI, State Machines, Research, Prototyping, Design, Obfuscation, Documentation, Landing Page Design, Landing Pages, IT Project Management, NATS
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