Michal is available for hire

Michal Kolodziejczyk

Verified Expert in Engineering

Software Developer

Location

Warsaw, Poland

Toptal Member Since

September 30, 2022

Michal is a software developer with 22 years of experience in programming with C# and 26 years of IT experience. He is most valued for professionalism, ease of sharing knowledge, testing his solutions, and openness to new ideas and programming methods. Michal's experience with Raiffeisen and Citi gave him a solid financial background needed for demanding projects.

Portfolio

Citi

C#, Couchbase, Microservices, Git, SQL Server 2016, .NET, Architecture...

Sygenic

Algorithms, Android, API Integration, APIs, Architecture...

Raiffeisen Leasing

.NET, Java, SQL, Design Patterns, Concurrent Programming, API Applications...

Experience

C# - 20 years .NET - 20 years ASP.NET - 18 years Solution Architecture - 15 years Architecture - 15 years Microservices - 10 years .NET Core - 6 years Solidity - 3 years

Availability

Part-time

Preferred Environment

C#, NoSQL, ASP.NET, .NET, Git, Microservices, Solidity, Back-end, Integration, Blockchain, SDKs, Windows, Windows App Development, Software Architecture, Algorithmic Trading, JSON, Linux, Apache, Google Sheets, Asynchronous Servers, Asynchronous Programming, Object-oriented Programming (OOP), Object-oriented Design (OOD), Cryptocurrency, Desktop App Development, Windows Desktop Software, Minimum Viable Product (MVP), API Design, A/B Testing, Machine Learning, .NET 6, Decision Trees, Agile, Open Source, API Documentation, Databases, Third-party APIs, HTTP, Scripting, MVC Design, SOLID Principles, SaaS, Design Patterns, Concurrent Programming, API Applications, Version Control Systems, Workflow, Microservices Architecture, SSL, Fintech, API Development, Sass, Process Automation, Business Services, IT Projects, Business Requirements, Blockchain & Cryptocurrency, Tokenization, Stock Exchange, Smart Contracts, Trading Systems, Software Design, Business Process Automation, API Management, Accounts, Product Design, Authentication, Technical Design, Technical Architecture, System Architecture Design, Ubuntu, Clean Architecture, Scrum, Encryption, Documentation, Technical Documentation, Component Libraries, Data Collection, Product Leadership, Database Design, Cryptocurrency Wallets, Domain-driven Design (DDD), Web Application Architecture, NGINX, WiFi, Team Management, Tags, ASP.NET Core, Technical Consulting, Stock Market, Enterprise Application Architecture, Web Applications, MVC Frameworks, User Authentication, XAML, Visual Studio, .NET MAUI, Data Structures, B2B, Engineering, Banking & Finance, Test Automation, Web Services, System Design, Product Development, Infrastructure, Optimization, Security, Back-end Architecture, CQRS, Automated Testing, Design Systems, Swagger, HTTP Server, Web 3.0, Technical Project Management, Bitcoin, Unit Testing, Business Analysis, Technical Requirements, IT Business Analysis, Application Architecture, Server-side Rendering (SSR), Bash, Ethereum, Gang of Four (GOF) Design Patterns, Excel Add-ins, Windows Packaging

The most amazing...

...thing I've created is a mobile application that won the German merchandising app competition.

Work Experience

SRE Engineer and EMEA Architect for Private Banking

2020 - 2022

Citi

Oversaw the process of certifying each programming language used at Citi.
Supervised the architecture of a private open banking solution.
Increased the efficiency of the Atlassian Bitbucket solution significantly and provided the Git repository reporting process for top management.

Technologies: C#, Couchbase, Microservices, Git, SQL Server 2016, .NET, Architecture, Solution Architecture, Leadership, Windows Presentation Foundation (WPF), Microsoft SQL Server, PostgreSQL, TypeScript, CSS, JavaScript, APIs, HTML, OpenAPI, Back-end, Back-end Development, Java, SQL, Technical Leadership, Full-stack, Node.js, Android, Web Scraping, PHP, Financial Modeling, REST APIs, Mobile Apps, REST, Front-end, Docker, Apache Kafka, Project Planning, Product Strategy, Jira, C++, Management, GitHub, Team Leadership, Code Generators, COM, Data Modeling, MySQL, API Integration, MetaMask, Blockchain, C, Integration, Unix, MariaDB, Test-driven Development (TDD), C#.NET, Crypto, Digital Banking, SDKs, Windows, Windows App Development, Software Architecture, Non-fungible Tokens (NFT), JSON, Linux, Apache, Cryptography, Google Apps Script, Google Sheets, Asynchronous Servers, Asynchronous Programming, Object-oriented Programming (OOP), Object-oriented Design (OOD), Webhooks, Cryptocurrency, IT Project Management, DevOps, Distributed Systems, Large Scale Distributed Systems, CI/CD Pipelines, Continuous Integration (CI), Continuous Delivery (CD), Kubernetes, Telecommunications, Telecom Equipment & Solutions, Multithreading, Data Processing, Realtime, Multi-language Support, Desktop App Development, Windows Desktop Software, Data Engineering, API Design, Technical Writing, Mobile Back-end, A/B Testing, Entity Framework, .NET 6, Decision Trees, Mobile, Agile, Mobile App Development, API Documentation, Full-stack Development, Databases, DNS, WebSockets, Third-party APIs, Mobile Banking, Mobile Applications, Mobile UI, Agile Software Development, HTTP, Scripting, MVC Design, SOLID Principles, Web Development, Trading, Design Patterns, Concurrent Programming, API Applications, Agile Software Testing, Version Control Systems, Workflow, Microservices Architecture, Stress Testing, SSL, Key Performance Indicators (KPIs), Fintech, API Development, Sass, CSHTML, ASP.NET Razor, MVC Razor, Microsoft Word, Process Automation, Business Services, IT Projects, Business Requirements, Blockchain & Cryptocurrency, Tokenization, Stock Exchange, Low Latency, Software Design, Business Process Automation, Microsoft Excel, API Management, Accounts, User Experience (UX), Widgets, Product Design, Single Sign-on (SSO), Authentication, Technical Design, Technical Architecture, Reports, System Architecture Design, System Administration, Automation, Ubuntu, Clean Architecture, Scrum, Networking, Encryption, Documentation, Technical Documentation, Component Libraries, Data Collection, Relational Databases, Product Leadership, Database Design, Cryptocurrency Wallets, Domain-driven Design (DDD), Web Application Architecture, NGINX, Networks, WiFi, Team Management, Tags, ASP.NET Core, Troubleshooting, Root Cause Analysis, Technical Consulting, Enterprise Application Architecture, Web Applications, MVC Frameworks, User Authentication, XAML, Visual Studio, Data Structures, B2B, Engineering, Banking & Finance, Test Automation, Web Services, System Design, Product Development, Infrastructure, Data Analytics, Optimization, ASP.NET MVC, OAuth, Security, Back-end Architecture, CQRS, Automated Testing, Design Systems, Swagger, HTTP Server, Web 3.0, ANSI SQL, Microsoft Office, Technical Project Management, Postman, Data Integration, Asymmetric Encryption, Unit Testing, Business Analysis, Technical Requirements, IT Business Analysis, IT Security, Functional Programming, Application Architecture, Server-side Rendering (SSR), Bash, Bitbucket, CSV, Company Databases, Test Automation Frameworks, Gang of Four (GOF) Design Patterns

Senior Developer, Lead Architect

2010 - 2022

Sygenic

Developed a full-stack system for a leasing company based on the orchestration of business processes.
Led the entire development team and was responsible for delivering the final products to the company's clients.
Created the architecture and key parts of the business process engine used to produce customer solutions.

Technologies: Algorithms, Android, API Integration, APIs, Architecture, Artificial Intelligence (AI), ASP.NET, Back-end, Back-end Development, Blazor, Blockchain, C, C#, C++, C#.NET, Code Generators, Communication, Computer Networking, Couchbase, Crypto, CSS, CTO, Data Modeling, Digital Banking, Docker, Enterprise Architecture, Financial Modeling, Front-end, Full-stack, Genetic Algorithms, Git, GitHub, Go, HTML, Integration, IT Systems Architecture, Java, JavaScript, Jira, Leadership, Management, MariaDB, MetaMask, Microservices, Microsoft SQL Server, Mobile Apps, MongoDB, MySQL, .NET, .NET Core, Node.js, NoSQL, Object-relational Mapping (ORM), OpenAPI, PHP, PostgreSQL, Product Strategy, Programming, Project Planning, Qt, RavenDB, REST, REST APIs, Rinkeby, Rust, Solidity, Solution Architecture, SQL, SQL Server 2016, Syncfusion, TCP/IP, Team Leadership, Technical Leadership, Test-driven Development (TDD), TypeScript, Unix, Visual Studio Code (VS Code), Web Scraping, Windows Presentation Foundation (WPF), Xamarin, Mobile Development, SDKs, Windows, Windows App Development, Software Architecture, Algorithmic Trading, Non-fungible Tokens (NFT), JSON, Linux, Apache, Cryptography, Google Apps Script, Google Sheets, USB, Asynchronous Servers, Asynchronous Programming, Object-oriented Programming (OOP), Object-oriented Design (OOD), Webhooks, Cryptocurrency, IT Project Management, DevOps, Distributed Systems, Large Scale Distributed Systems, CI/CD Pipelines, Continuous Integration (CI), Kubernetes, Telecom Equipment & Solutions, Multithreading, Data Processing, Realtime, Visual Studio 2016, Multi-language Support, Desktop App Development, Windows Desktop Software, Data Engineering, Minimum Viable Product (MVP), API Design, Technical Writing, Mobile Back-end, A/B Testing, Machine Learning, Entity Framework, .NET 6, Decision Trees, Mobile, Agile, Mobile App Development, Open Source, API Documentation, Visual Basic, Full-stack Development, Databases, DNS, Third-party APIs, Mobile Applications, Agile Software Development, HTTP, Scripting, MVC Design, SOLID Principles, Web Development, Software Engineering, SaaS, Design Patterns, Concurrent Programming, API Applications, Agile Software Testing, Version Control Systems, Workflow, Microservices Architecture, Stress Testing, eCommerce APIs, SSL, Key Performance Indicators (KPIs), Fintech, API Development, Sass, CSHTML, ASP.NET Razor, MVC Razor, Microsoft Word, Process Automation, Business Services, IT Projects, Business Requirements, Software Design, Business Process Automation, Microsoft Excel, API Management, Accounts, User Interface (UI), User Experience (UX), Widgets, Product Design, Authentication, Technical Design, Technical Architecture, Reports, System Architecture Design, System Administration, Automation, Ubuntu, Clean Architecture, Networking, Encryption, Documentation, Technical Documentation, Component Libraries, Data Collection, Relational Databases, Product Leadership, Database Design, Domain-driven Design (DDD), Web Application Architecture, NGINX, Networks, WiFi, Team Management, Tags, ASP.NET Core, Troubleshooting, Root Cause Analysis, Technical Consulting, Enterprise Application Architecture, MVC Frameworks, User Authentication, XAML, Visual Studio, Data Structures, B2B, Engineering, Banking & Finance, Test Automation, Web Services, System Design, Product Development, Infrastructure, Data Analytics, Optimization, ASP.NET MVC, OAuth, Security, Back-end Architecture, CQRS, Automated Testing, Design Systems, Swagger, HTTP Server, ANSI SQL, Microsoft Office, Technical Project Management, Postman, Data Integration, Asymmetric Encryption, Unit Testing, Business Analysis, Technical Requirements, IT Business Analysis, IT Security, Functional Programming, Application Architecture, Server-side Rendering (SSR), Bash, Bitbucket, CSV, Company Databases, Test Automation Frameworks, Gang of Four (GOF) Design Patterns

Lead Architect

2008 - 2010

Raiffeisen Leasing

Completed system analysis and use cases for the new core platform aggregating all sales processes for the corporation.
Managed the execution and implementation of reporting for the state financial supervision, which was a necessary condition to obtain the required licenses and approvals.
Implemented a service-based architecture for most of the key native applications used by the corporation, which allowed, among other things, for more efficient sales management and reduction of business costs.

Technologies: .NET, Java, SQL, Design Patterns, Concurrent Programming, API Applications, Version Control Systems, Workflow, SSL, Hibernate, Fintech, API Development, ODBC, Process Automation, Business Services, Visual Basic for Applications (VBA), IT Projects, Business Requirements, Software Design, Business Process Automation, Microsoft Excel, API Management, Accounts, Widgets, Product Design, OAuth 2, Authentication, Technical Design, Technical Architecture, Reports, System Architecture Design, Active Server Pages (ASP), Automation, Ubuntu, Clean Architecture, Networking, Documentation, Technical Documentation, LAMP, Component Libraries, Data Collection, Relational Databases, Product Leadership, Database Design, Web Application Architecture, WiFi, Team Management, Tags, Troubleshooting, Root Cause Analysis, Technical Consulting, Enterprise Application Architecture, MVC Frameworks, User Authentication, Visual Studio, Data Structures, B2B, Engineering, Banking & Finance, Test Automation, Web Services, System Design, Product Development, Infrastructure, Optimization, ASP.NET MVC, Security, Back-end Architecture, CQRS, Automated Testing, Design Systems, Swagger, HTTP Server, ANSI SQL, Microsoft Office, Technical Project Management, Data Integration, Unit Testing, Business Analysis, Technical Requirements, IT Business Analysis, Application Architecture, Server-side Rendering (SSR), Bash, CSV, Company Databases, Test Automation Frameworks, Gang of Four (GOF) Design Patterns

Chief of Architecture

2001 - 2008

Raiffeisen Bank

Created the architecture and key parts of a middleware solution based on the IBM MQ Series, which combined 150+ systems used in the bank.
Built the architecture and supervised the implementation of the internet transactional platform for corporate banking.
Developed the first mobile banking solution in Poland, including programming, architecture, and encryption.

Technologies: Java, .NET, HTML, CSS, C, C#, C#.NET, C#.NET WinForms, C++, MQSeries, SQL, SQLite, SQL Server 2016, SQLite.NET, SQLiteManager, Mobile Development, SDKs, Windows, Windows App Development, Software Architecture, JSON, Linux, Apache, Cryptography, Google Sheets, Asynchronous Servers, Asynchronous Programming, Object-oriented Programming (OOP), Object-oriented Design (OOD), IT Project Management, Telecom Equipment & Solutions, GSM, Multithreading, Data Processing, Visual Studio 2016, Multi-language Support, Desktop App Development, Windows Desktop Software, Data Engineering, API Design, Technical Writing, A/B Testing, Decision Trees, Mobile App Development, API Documentation, Visual Basic, Full-stack Development, Databases, DNS, JUnit, Third-party APIs, Mobile Banking, Mobile Applications, HTTP, MVC Design, SOAP, SOLID Principles, Web Development, Design Patterns, Concurrent Programming, API Applications, Version Control Systems, Workflow, SSL, Hibernate, API Development, ODBC, Process Automation, Business Services, Visual Basic for Applications (VBA), IT Projects, Business Requirements, Software Design, Business Process Automation, Microsoft Excel, API Management, Accounts, Product Design, Single Sign-on (SSO), Authentication, Technical Design, Technical Architecture, Reports, System Architecture Design, Active Server Pages (ASP), Ubuntu, Clean Architecture, Networking, Documentation, Technical Documentation, LAMP, Component Libraries, Data Collection, Relational Databases, Product Leadership, Database Design, Web Application Architecture, Delphi, WiFi, Team Management, Tags, Troubleshooting, Root Cause Analysis, Technical Consulting, Enterprise Application Architecture, MVC Frameworks, User Authentication, Visual Studio, Data Structures, B2B, Engineering, Banking & Finance, Test Automation, Web Services, System Design, Product Development, Infrastructure, Optimization, Security, Back-end Architecture, CQRS, Automated Testing, Design Systems, HTTP Server, Technical Project Management, Data Integration, Unit Testing, Business Analysis, Technical Requirements, IT Business Analysis, Application Architecture, Server-side Rendering (SSR), Bash, CSV, Company Databases, Gang of Four (GOF) Design Patterns

Experience

Titan

Titan is a framework for a quick definition, orchestration, and management of business processes with the automatic generation of forms and tabular data and a set of ready-made processes for business management. Data is stored on one of three NoSQL database engines while all system functions and business processes are available using JSON REST API. The framework enables authentication and authorization with internal accounts, Active Directory, Google, Facebook, and OAuth. The front end is developed using Blazor, HTML, CSS, and Syncfusion components.

Forget-me-not

A marketing system that links outdoor advertising with the geolocation of a mobile phone user. The system consists of an iOS and Android application, a front-end part for advertisers, and a back-end part that settles all system elements and manages finances, complaints, promotions, and reporting.

Security Incidents in Food Warehouses

A system for Nestle to report, supervise, repair, and report any incidents related to the physical safety of employees and products in high-bay warehouses. I developed the web front end and mobile applications for iOS and Android, as well as the complete process back end for supervision of all processes related to incidents. It is worth mentioning that after the system implementation, the number of fatal accidents in warehouses using the system dropped to zero.

Education

1998 - 2000

Master's Degree in Computer Science

Polish-Japanese University of Information Technology - Warsaw, Poland

1995 - 1998

Engineer's Degree in Computer Science

Polish-Japanese University of Information Technology - Warsaw, Poland

Certifications

JUNE 2017 - PRESENT

Xamarin Certified Mobile Developer

Xamarin University

JULY 2007 - JULY 2013

TOGAF 8

The Open Group

Skills

Languages

C#, C#.NET, Sass, ASP.NET Razor, Solidity, TypeScript, HTML, Visual Basic, Visual Basic for Applications (VBA), Active Server Pages (ASP), Delphi, XAML, Bash, Rust, CSS, JavaScript, Java, SQL, Go, PHP, C++, C, Google Apps Script, HTML5, WASM, CSS3

Frameworks

.NET, .NET Core, MVC Razor, ASP.NET Core, ASP.NET, Blazor, JUnit, ASP.NET MVC, Swagger, Windows Presentation Foundation (WPF), Bootstrap, Qt, Realtime, Hibernate, OAuth 2, Unity

Libraries/APIs

REST APIs, API Development, OpenAPI, SQLite.NET, Entity Framework, ODBC, Node.js, Google API

Tools

Visual Studio, Git, C#.NET WinForms, SQLiteManager, Google Sheets, Microsoft Word, Microsoft Excel, NGINX, Syncfusion, Jira, GitHub, MetaMask, MQSeries, Apache, Postman, Bitbucket

Paradigms

REST, Management, Windows App Development, Asynchronous Programming, Object-oriented Programming (OOP), Object-oriented Design (OOD), Model View ViewModel (MVVM), Desktop App Development, MVC Design, Design Patterns, Microservices Architecture, Clean Architecture, Web Application Architecture, Enterprise Application Architecture, B2B, Test Automation, Back-end Architecture, CQRS, Unit Testing, Application Architecture, Microservices, Object-relational Mapping (ORM), Test-driven Development (TDD), Agile, Concurrent Programming, Stress Testing, Automation, Database Design, Automated Testing, Gang of Four (GOF) Design Patterns, Mobile Development, DevOps, Continuous Integration (CI), Continuous Delivery (CD), Mobile App Design, Agile Project Management, Agile Software Development, Scrum, Functional Programming

Platforms

Windows, Visual Studio 2016, Blockchain, Unix, Linux, Mobile, Ubuntu, Visual Studio Code (VS Code), Xamarin, Android, Docker, Apache Kafka, Kubernetes, iOS, LAMP, Ethereum

Industry Expertise

Project Management, Banking & Finance, Telecommunications, Trading Systems

Storage

JSON, Data Integration, Company Databases, SQLite, Databases, NoSQL, RavenDB, Couchbase, MongoDB, SQL Server 2016, Microsoft SQL Server, PostgreSQL, MySQL, MariaDB, Relational Databases, ANSI SQL

Other

Programming, Architecture, IT Systems Architecture, Enterprise Architecture, Solution Architecture, Leadership, APIs, Back-end, Back-end Development, Technical Leadership, Financial Modeling, Project Planning, Team Leadership, Code Generators, Data Modeling, API Integration, Integration, CTO, Crypto, Digital Banking, SDKs, Software Architecture, Algorithmic Trading, Asynchronous Servers, Multithreading, Multi-language Support, Windows Desktop Software, Data Engineering, Minimum Viable Product (MVP), API Design, Technical Writing, Mobile Back-end, A/B Testing, .NET 6, Decision Trees, API Documentation, IT Projects, Third-party APIs, Mobile Banking, Scripting, SOLID Principles, Software Engineering, SaaS, API Applications, Workflow, SSL, Fintech, CSHTML, Process Automation, Business Services, Business Requirements, Software Design, Business Process Automation, API Management, Accounts, Product Design, Authentication, Technical Design, Technical Architecture, System Architecture Design, Documentation, Technical Documentation, Component Libraries, Data Collection, Product Leadership, Tags, Technical Consulting, MVC Frameworks, Proof of Concept (POC), Data Structures, Engineering, System Design, Product Development, Infrastructure, Design Systems, Server-side Rendering (SSR), CSV, Excel Add-ins, Artificial Intelligence (AI), Genetic Algorithms, Algorithms, TCP/IP, Computer Networking, Web Scraping, CRM APIs, Communication, Rinkeby, Non-fungible Tokens (NFT), Cryptocurrency, IT Project Management, Distributed Systems, Data Processing, Mobile App Development, Open Source, DNS, WebSockets, Mobile Applications, HTTP, Web Development, Trading, Agile Software Testing, Version Control Systems, Key Performance Indicators (KPIs), Blockchain & Cryptocurrency, Tokenization, Smart Contracts, Reports, System Administration, Networking, Cryptocurrency Wallets, Domain-driven Design (DDD), Networks, Team Management, Troubleshooting, Root Cause Analysis, Data Analytics, Optimization, HTTP Server, Web 3.0, Microsoft Office, Technical Project Management, Business Analysis, Technical Requirements, IT Business Analysis, Full-stack, Mobile Apps, Front-end, Product Strategy, COM, eCommerce, Cryptography, USB, Webhooks, Large Scale Distributed Systems, CI/CD Pipelines, Telecom Equipment & Solutions, GSM, WebAssembly, Machine Learning, Full-stack Development, Reporting, Mobile UI, SOAP, eCommerce APIs, Stock Exchange, Low Latency, User Interface (UI), User Experience (UX), Widgets, UI Animation, Single Sign-on (SSO), Encryption, QA Testing, WiFi, Stock Trading, Stock Market, Web Applications, User Authentication, .NET MAUI, Web Services, OAuth, Security, Bitcoin, Asymmetric Encryption, IT Security, Test Automation Frameworks, Windows Packaging

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